One the reasons Apple's (NASDAQ:AAPL) iPhone was and remains successful is the tremendous support the smartphone got from developers.

Though many apps are also developed for or ported to the Android operating system and some even to Microsoft's (NASDAQ:MSFT) Windows Phone, it's very rare for a popular app to not be released on iOS. This support has allowed Apple to remain a major player in smartphones despite having only 18.3% market share as of the first quarter of this year, compared with 78% for Android, according to IDC.

Developers know that Apple's iPhone user base makes them money, as they have experienced it over many years. The same has not yet been proved for Apple Watch, and that could cause the company a major headache.

Because the watch is not a proven product, many developers and the owners of major apps have taken a wait-and-see attitude about developing for it., according to The New York Times.

Apple Watch

A lack of apps could be a major problem for Apple Watch. Photo by author.

Why is this happening?
While Apple has yet to release sales figures for its watch, it's safe to see it has a much smaller user base than iPhone. Analysts pin the number of smartwatches the company has sold at between 3 million and 5 million. That's not a terrible start for a product, but it's a relatively small universe for an app developer to program for.

Perhaps more importantly, Apple failed at trying to get major players such as Facebook
(NASDAQ:FB) on board when it launched the watch. Adam Mosseir, who oversees Facebook's news feed, told The Times the company has been looking at Apple Watch, but he blamed the form factor -- not the small audience -- for his company's failure to release a dedicated Apple Watch app.

"I don't know if we could get it all in there in a way that feels good and works well," Mosseri told the paper. "You'd just want to get your phone out at that point."

That may be true, but it rings a little hollow when you see that the company had built versions of its Messenger and WhatsApp platforms for early versions of Android watches. The company may deny it, but it seems that if Apple had tens of million of Watch users, the small-screen problem could be overcome.

How bad is it?
Facebook is missing, as are Snapchat and Google. In fact, only five of the 20 most popular free iPhone apps are available on Apple Watch, according to data from App Annie cited by The Times.

In a broad sense, Apple Watch has the same problem Windows Phone does. It's not a pure shortage of apps; it's the lack of the ones people actually want that causes problems.

The Apple Watch store has over 7,400 apps -- probably more than enough if most of the top ones were, but they aren't. It's probably also troubling that the Watch app store is growing slower (a 142% increase) than the iPhone store did in its first three months (it jumped 437%), according to App Annie.

It's a dilemma that affects every phone and tablet not running Android or an Apple operating system. For users, it doesn't matter how good your device is if it's lacking in apps. For developers, if the user base isn't there, then most simply won't expend the resources even when it's for Apple.

Can Apple solve this?
To figure out this problem, Apple will have to do some things it doesn't normally do. First, it needs to do whatever is necessary to bring most of the top apps to the platform. If that means paying companies such as Facebook to create and maintain an app, then it must do exactly that.

After that, Apple needs to accept that its watch may not enjoy the sudden rise of its sister products. Instead, it may need to grow in a more measured way, as the company entices app developers to come on board while also developing its own apps that make people want the device.

This is a new world for Apple, which has generally enjoyed nearly universal support from developers, but it hasn't been proved that any smartwatch will succeed, let alone Apple Watch. To make its new product a success, the company needs to grow its app base and its user base together. That's a tough task, but Apple has the deep pockets to do it.

Daniel Kline owns shares of Apple, Facebook, and Microsoft. He's pretty sure that no app can convince him to buy a smartwatch. The Motley Fool recommends Apple, Facebook, Google (A shares), and Google (C shares). The Motley Fool owns shares of Apple, Facebook, Google (A shares), and Google (C shares). Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.