As users generally don't even think about, let alone make buying decisions about, who's getting what cut of the $2 price of a video game or the $7 price of some ebook, I don't think it would have mattered.
With higher quality apps on the Market, Android owners might be more willing to fork over money for them.
Not really. I think the teams that were going to branch out largely did and still do. And from the results we keep hearing, I don't think a smaller cut is going to change any minds of those who decided against it.
As to more good for-pay apps leading to more purchasing, I don't know that would necessarily follow. Particularly not after the Angry Birds experience seemed to suggest direct sales weren't even that great for a game at the level of a cultural phenomenon.