As a primarily-iOS user / developer who also has an Android tablet (last year's Nexus 7), completely agree with both points made here. [The first being that Android development is better, and the second being that the vast majority Android apps currently suck compared to the iOS equivalent, making for a nice opportunity.]
It's hard enough to peg a real user need and deliver on that need in a satisfying, sticky way. It's at the core of what a startup needs to do to cultivate that product development discipline as a team, and tools that make that harder are insult to injury.
As others have mentioned, though, none of these app startups are launching just for a smooth development experience. And Android just hasn't shown that users will reliably upgrade their OS, much less pay for apps like iOS users do. Until that changes, even if the better dev experience will accelerate a shift, it's sort of a chicken-and-egg problem on app quality.