I wonder how long till we see more games hitting android first. It's usually done ios then android due to the slightly shorter development time needed for ios. But I've seen a few companies start experimenting with launching on Android first.
From what other people are saying here, the reason that iOS is getting the games first is because iOS users are more likely to buy in-app things. So the developers use that to get funding to continue making more software and eventually bring it over to Android.