The idea of "one or more" stores distributing these apps seems likely to hurt profit margins for developers. I was intrigued until they mentioned that aspect.
In other words, nobody will be forcing these developers to be on a particular store -- unlike Apple's App Store, where you have to play on their terms.
If someone could launch a competitor to the Apple App store, and say "I'm going to take half the margin that apple takes from app developers", I think developers would flock to that store, and then so would customers.