If there is one thing that cannot be disputed, it is that both iOS and Android have more apps in their app store compared to Windows Phone. This is hardly surprising as Windows Phone is not the most popular platform, so why would developers want to bother? In a way it almost feels like Windows Phone is like the Wii U of smartphones, where despite it being a decent platform, it commands a lower user base due to there not being enough apps (one of the reasons), and its low user base has discouraged developers from creating for it. That being said, Statistic Brain has put together some numbers which might surprise you.
According to their data, they have found that Android is the leader in downloads, however despite that, their app revenue is around $1.2 billion. This is no small figure but in contrast to Windows Phone whose app downloads is only a fraction of Android, their app revenue is at $0.95 billion, which is pretty close to what Android is making. Statistic Brain breaks it down further and finds that Windows Phone developers essentially make on average about $0.23 per download, versus Android developers who only make $0.04. As for iOS, they are leading in app revenue at $6.4 billion which puts them at $0.24 per download.