In a press release, an ABI research associate chalked this up to to the fact that Android platform is open, allowing any developer to create and distribute any app:
Being a free platform has expanded the Android device install base, which in turn has driven growth in the number of third party multi-platform and mobile operator app stores. These conditions alone explain why Android is the new leader in the mobile application market.
In addition, Android phones are finding their way into the hands of more and more users, therefore it's not a huge surprise that more Android apps are being downloaded. According to comScore's August report on mobile market share, almost 44 percent of smartphone owners have Android phones while 27 percent have iPhones. These numbers closely resemble ABI's percentages for Android and iOS app market share.
The ABI study nods to the disparity between the number of Android and iOS supporting handsets. According to their report, iPhone shipments decreased by 6 percent in the second quarter, while Android shipments increased 16 percent. Apple expects next quarter's iPhone sales to be much higher and has speculated that the drop in iPhone shipments was probably partly due to consumers holding off on buying new phone until the iPhone 4S came out.
While fewer people have iPhones, they download more apps each than Android users do. In fact, Apple is beating Android 2-to-1 in terms of app downloads per user. The ABI report attributes this to, "Apple's superior monetization policies attracted good developers within its ranks, thus creating a better catalog of apps and customer experience."
Business Insider writes that this distinction is important for Apple because it means developers will continue working with them even though Android has more users, "For now, developers are still happier with iOS despite the smaller user base and smaller number of total downloads."
Even though it's easier for developers to get apps into the Android Market, at least some of them prefer Apple's strict vetting process that keeps bad apps out. In an interview with The Huffington Post, one developer said that the quality of apps on the Android Market was "pathetically low." Which may be why the ABI report found that the number of app downloads per iOS user was twice as high as that of Android users.
While Android may be dominating the smartphone market in terms of units sold and apps downloaded, Apple is the clear winner when it comes to tablets. According to Mashable, Apple's tablet market share as of April 2011 was around 83 percent. While some report that sales of Android tablets have started to catch up with Apple's iPad sales, PC World thinks Android's tablet numbers are being inflated by "shaky math" and clever semantics. While Apple usually reports tablet figures in terms of how many have been sold, Android often talks in terms of how many are shipped. It sounds impressive to say 250,000 tablets have been shipped, but not if 95 percent of them are sitting in a warehouse somewhere unable to be sold.