The iPad Pro may have just been shelved, according to Digitimes. For investors closely following the Apple rumor mill, this may come as quite a surprise. Up until now, speculation pointed to an eventual launch of a larger iPad. But should investors be surprised? After all, Apple (NASDAQ:AAPL) is known for unashamedly shelving product plans at the last minute. Even more, does Apple rumor speculation really help investors?

A MacRumors mockup of a 12.9-inch iPad next to a 13-inch Macbook Air. Photo used with permission.

Apple's secrecy makes speculation almost impossible
When Apple CEO Tim Cook said in 2012 that it was "going to double down on secrecy on products," he apparently wasn't kidding. Despite Cook's assertion that Apple is working on "new categories," and the fact that the company's massive supply chain sprawls the globe, it has been very difficult for the ever-active Apple rumor mill to pinpoint exactly what Apple is working on this year. And now with Apple reportedly shelving plans, it's a wonder if investors can make any accurate predictions of Apple's product plans.

In one example of just how difficult it is this year to predict Apple's product plans, analysts still remain undecided on the purpose of Apple's contract with GT Advanced Technologies to produce enough sapphire crystal for up to an estimated 25 million smartphone covers a quarter.

Is Apple's secrecy and unpredictability calling into question the entire relevancy of the Apple rumor mill for Apple investors?

The impact on Apple's business is hard to estimate
Even if we could be sure Apple was launching an iPad Pro, it would be very difficult for investors to predict the impact it could have on its business. Generating $174 billion of revenue in the trailing 12 months, new products would have to both be a blockbuster success not over cannibalization Apple's other product lines to meaningfully budge Apple's bottom line.

Fortunately, investors who own Apple stock today don't need to predict Apple's product launch plans to justify holding on to the stock. Trading at just 13 times earnings with a the world's largest share repurchase program in effect, any major success of a new product would likely be a bonus for the company. Further, given Apple's incredible customer retention along with Apple's proven track record of successful new products, Apple's user base likely won't be going anywhere.

So will we ever see an iPad Pro? It's tough to say. But does it really matter whether we can accurately predict Apple's product plans or not?

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.