iOS Usage Information is years out of date.
In you appstore rant you reference an article as the source for the 50 million iOS users statement. That article is from 2011. As of Feb. 27th 2020 according to https://www.statista.com/statistics/232790/forecast-of-apple-users-in-the-us/#statisticContainer in the US alone there are more than 101 million iPhone users. Apple reports they have 1.5 billion active devices world wide in their 1st quarter earnings call. Speaking exclusively about app stores you should probably look at SmartPhone global market share instead of iOS users alone. Almost all variations of Android phones include an app store as well. The information you provided is out of date and misleading.