Hey, for 99c software it might work (but still being less profitable than other platforms), and that's the reason iTunes can work, too (the single unit costs very little). However, at that point you put a brake on complex (commercial) software that requires serious budgets (how strong a platform needs to be to sustain development and marketing of something like, say Real Racing for 99c ?).

What you're talking about is not commercial development - it's a formalized donation scheme. It's OK but it IS a marked difference.