When you combine all the titles in Apple’s App Store with those in Google Play, you have a catalog of more than 1.4 million apps from hundreds of thousands of developers. But incredibly, more than 50% of the revenue made by these stores in the United States goes to just 25 app developers.

Analytics firm Canalys performed a daily survey over a 20-day period in November and found that just 25 Android and iOS developers accrued $60 million from paid downloads and in-app purchases. What’s more, all the top-grossing developers — except for one, Pandora — are games developers, with Electronic Arts, Disney, Kabam, Glu, Gameloft, Storm8, and of course Rovio on the list.

Canalys found that 145 of the top 300 paid apps in the App Store were games, while 116 of the top 300 paid apps in Google Play were games. Games also made up 94 of the top 300 free apps in the App Store, and 110 of the top 300 in Google Play.

Canalys senior analyst Tim Shepherd noted that due to the huge selection of titles available in these stores, discoverability is one of the biggest issues independent developers face. “With top game developers’ content so prevalent in the stores, it can be hard for other good quality apps to get the attention they deserve,” he told TechCrunch.

“Developers of other kinds of apps need to consider how to promote them. Depending on the type of app, they should consider how best they can exploit social media and social recommendations, tactical sales promotions and discounts, branding tie-ups and targeted in-app advertising.”

All of the large developers have become successful with multiple titles, Canalys notes. Zynga had 15 titles “on average” in the list of top 300 grossing iPhone apps in the App Store, and nine titles in top-grossing list on Google Play. Angry Birds creator Rovio also had “multiple game variants” included in the list.

It’ll only get harder for independent developers to get their titles noticed over the holidays, too. Canalys expects many of the top 25 developers to strengthen their dominance over Christmas by “employing discounts and special offers, taking advantage of their ability to cross-promote within their app portfolios.”

“This is expected to ensure that over the Christmas period in the US, the dominance of key game developers will only increase,” said Canalys VP Chris Jones.

Will developers turn to other platforms for recognition? Apparently not. According to AdAge, developers appear to be showing little interest in Microsoft’s Windows Phone platform, despite being offered “more favorable” revenue splits that those offered by Apple and Google. Microsoft offers 70% of app revenue until titles surpass $25,000 in revenue, at which point they get 80%.

, AdAge

• SourceTechCrunch