It will never reach that "maturity" level, since it goes against what Android actually is. Freedom to choose what device/power/budget you need.
See, I understand that, but I think that's actually not correct. Case in point: there already IS a consistent baseline of hardware that nothing goes below. No phone has less than a certain amount of CPU power, because it just makes no sense to have a phone with less and it doesn't cost any less to make them weaker than that. You can't find processors that bad, etc.
The problem is that baseline is super low right now. 5 or 10 years from now, though? What will the baseline be of "you can't buy a wholesale processor worse than this, or RAM smaller than this?" In that regard it's not a matter of all the Android folks organizing, it's a matter of the market maturing. For instance, right now I'm pretty sure it's impossible for me to buy a 200MHz laptop, but nobody made that an edict. It just isn't something that would even happen now. It's a pretty safe bet that almost everything has 1.6Ghz in terms of even netbooks these days. 1Ghz at worst, but I've not seen anything like that in a long time.
Standardization of screen sizes is also something that doesn't have to come from edicts. It comes from a desire to do things cheaply. There are only so many screen sizes for actual PCs, for instance. It's about 10 sizes to support, in pretty close to two aspect ratios, not 50. As phones and tablets mature, I would be surprised if some sizes didn't become preferred over all others, leading to a market shift simply because manufacturers want to jump on that bandwagon both for marketing and for cost reasons.
In terms of customers being willing to actually buy apps more... I think that if their phones had better hardware across the board and thus the app experience was better, that would change. And a few stronger stores than what is there right now, too. So that could change, but it will take a while.
In other words, I'm talking pretty far out, but I think that sort of maturity will happen even with this remaining as open as it is. Just look at the PC, you know?