I suspect that the way the carriers each demand slightly different feature checklists and releasing a new phone every month (c.f. http://en.wikipedia.org/wiki/List_of_Android_devices#Samsung and http://en.wikipedia.org/wiki/List_of_HTC_phones#A_Series_.28... ) means their hardware engineering budget is much larger than Apple's, and their software budget isn't far behind.

The margins on Androids simply aren't high enough to justify the costs of making one-time customers into fans or repeat buyers.