There aren't enough superlatives in the English language to describe the excitement of analysts over the tablet segment. iSuppli now anticipates that nearly a quarter billion tablets will be sold in 2015. Apple (Nasdaq: AAPL) is seen as losing its market dominance, but it could sell almost 370 million iPads before then -- and rake in more than $200 billion along the way. As much as analysts are hyping the tablet these days, you can only hope that the economy will play along in this crazy game and tablet manufacturers keep their feet on the ground.

A well-respected analyst once warned me to take any long-term sales and shipment forecast with a grain of salt. Just because an analyst says a certain shipment number will be reached at some point in time does not mean that there is truth to such a claim. It is merely a best guess on trends that excludes events no one can foresee with a distance of several years -- events such as the most recent recession that was triggered by the mortgage crisis. In addition, forecasts always include an effort to please a client base and make a company or market segment feel good about its business. (The DRAM industry appears to be especially easy to fool every year. I have no idea why those guys still listen to market forecasts, adjust their business accordingly, and go nearly bankrupt every other year.)

No accusations here, but occasionally, you do wonder where those long-term forecast numbers come from and how it's possible for anyone to predict any shipment number of any product five years down the road and make a credible sales pitch to a client and an even more credible PR pitch to media outlets. Perhaps we just love those dramatic numbers.

The current tablet hype is without doubt the craziest forecasted poker game I have ever witnessed in my career as a tech journalist. (Wait, there is an exception -- those silly dot-com predictions more than a decade ago.) If you buy into the current tablet predictions, the only plausible conclusion must be that every single business with a sense for profitability needs to build tablets. Right now.

Really? I'm not so sure.

Tablet forecast history and update: 242 million tablets in 2015
Let's look at the numbers and see how wrong the analysts have been just within the past 12 months.

In May 2010, IDC estimated that about 7.6 million tablets could be sold during the year. The market potential for 2014 should be in the range of 46 million units annually, the company predicted. In June, Forrester said that 3.5 million tablets would be sold in 2010 and up to 20.4 million devices in 2015. Remember, this was already two months after the iPad had become available. It was a time when analysts began revising iPad shipment expectations almost on a weekly basis, and it appeared to be a game in which the highest estimate got the privilege to dominate IT headlines.

In October, Gartner made a brave move to forecast 19.5 million shipped tablets for 2010 (six times the Forrester number), 54.8 million units for 2012, and 208 million for 2014. Forrester changed its conservative numbers in January to 24.1 million devices for 2010 (an increase of about seven times -- ooops), 42 million for 2014, and 44 million for 2015. So do you believe Gartner or Forrester? Well, you could always consider another set of numbers from the Yankee Group, which said in January that the tablet segment hit 15.7 million units in 2010 and will reach 81 million units in 2012. Or what about IDC? IDC said 17 million tablets were sold in 2010 and that 44.6 million will be sold in 2011 and 70.8 million in 2012. Good luck building your product strategy based on those numbers.

If you aren't confused already and you still don't want to make up your own numbers, but you want to feel much better about the overall market opportunity, you should consider iSuppli's latest market-forecast update: 19.7 million tablet units in 2010, 67 million in 2011, 120 million in 2012, 206 million in 2014, and 242 million in 2015.

If the Yankee Group is right, then the average tablet price will drop to $238 in 2015, which means that tablet manufacturers will serve a $58 billion market -- if iSuppli is right and if Yankee is right (at the same time), which is about as likely as having Microsoft (Nasdaq: MSFT) take over the smartphone market this year.

Let's dive into the silliness of these numbers a bit more. I won't think too much about the ecosystem factors that need to perfectly work out for each manufacturer in order to make iSuppli's numbers work, and I won't think too much about the fact that we haven't really figured out how these expensive (3G, 4G) tablets are exactly useful beyond the initial excitement and worth several hundred dollars to get them out of the store and possibly about $2,000 over a two-year period. However, iSuppli's crystal ball suggests that Apple will sell 43,713,714 iPads this year, 61,581,090 in 2012, 76,175,808 in 2013, 83,031,631 in 2014 and 88,013,529 in 2015.

All right. I get it. It's a forecast model. But pinning the numbers down to the last unit over five years looks suspicious to me, especially since there is no margin of error provided. (I feel terrible for the guy who has to come up with that number and justify it later on.)

In total, iSuppli believes that Apple will be selling about 367.6 million iPads between 2010 and 2015. Apple recently told us that the average iPad price is currently at $628, and if we assume that there will be no price deterioration until 2015, then the iPad should deliver a $231 billion business for Apple until the end of 2015. Or a $27.5 billion business in 2011. Is Apple betting on this number? Or on $55.2 billion iPad revenue in 2015?  I have no idea. If we go by the 2010 trend, then the current forecasts are way too low anyway and we may need a revision next month.

Putting everything in perspective
So if you have all your analyst subscriptions printed and spread out in front of you, then you would have the original lowest market forecast for tablets in 2010 at 3.5 million units and the actual result somewhere between 15.7 million and 19.7 million units, depending on whom you believe. You could have made up your own number that would have been as useful as every other number we read last year. The conclusion can only be that the market is too young to sustain a reliable short-, mid- or long-term forecast. If you trust any number at this time, good luck with that. Only a fool would bet the farm and a business on any forecast for the tablet market right now.

The numbers are all over the place, but there seems to be a consensus that the demand for tablets is increasing rapidly, which seems to be based on the demand for the iPad and early numbers for the Samsung Galaxy Tab, which, if we're honest, isn't an especially great tablet. The earliest time when more credible forecasts can be made is when we're seeing the impact of the first Android 3 tablets, such as the Motorola (NYSE: MOT) Xoom, and when we can quantify the demand for other substantial contenders such as Research In Motion's (Nasdaq: RIMM) PlayBook.

The current forecasts somewhat remind me of the market predictions for the early webpads more than 10 years ago, and the tablet PC. In 2001, Bill Gates "predicted" that the tablet PC would be the most popular PC form factor by 2006. In late 2001, it was not uncommon to hear about an annual shipment potential of 25 million to 50 million units annually. However, by 2003, IDC estimated the volume of tablet PCs at just 600,000 units. The segment (the original tablet PC form factor, also described as convertible notebooks) has turned into a niche for vertical markets, and shipments are currently estimated at less than 3.5 million annually. In fact, the market has seen some unintended cannibalization from the UMPC concept, which was incredibly hyped by Intel (Nasdaq: INTC) and Microsoft in 2006. It has, however, faded away in the professional market and never materialized in the consumer market.

I have to admit, the tablet PC of 2001/2002 had a much more difficult start than the tablet today. The average tablet PC was handicapped by a very limited battery running time, high price tags that started in the $2,000 range and the fact that wireless networks were just emerging. The UMPC was, in retrospect, an evolution of the tablet PC in a substantially smaller form factor, but screwed up in its core. Instead of an always-connected ultra-cool compact computer, we were given underpowered, overpriced, bulky, and power-hungry small tablets that lacked a user-friendly interface. And when the connectivity was finally there, Samsung messed up the keyboard layout (split in two halves on the left and right side of the screen, put a heavy hard drive into it, and charged a ridiculous $1,000 for it.

For both products, the time and the market were different, and the demands and expectations from customers have changed substantially. Apple has opened the eyes of Microsoft and Intel (and its partners). Whether you like Apple or not, you will have to give the company credit for figuring out how to make smartphones and tablets work. Today, tablets are much more compatible with technologies we expect to evolve within the next five years -- such as thin clients and cloud computing.

There is little doubt that tablets will sell much better than webpads, tablet PCs, and UMPCs, but I'm not going to make any numbered forecasts. However, I will predict that iSuppli's forecast of 88 million iPads in 2015 and 243 million tablets in 2015 (88 million iPads, 115 million media tablets, 39 million PC tablets) won't be even close. I'll update this article in January 2016.

Or in March 2011. 

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