One way to deal with app platform fragmentation is to develop your app using a technology that supports multiple platforms -- Sencha Touch comes to mind as one example. Not that it solves the problem entirely, but it does make it cheaper.

I'm not sure what makes the app ecosystem that much different from the web at large -- if anything, I think the amount of trite, junky apps mirrors the amount of useless noise found on the web in general.

He does make a good observation about there being an opportunity for some startup to come along and do to apps what google did to the web.