For what it's worth, I support and applaud Martin's decision to leave the Mac App Store. The details have already been discussed extensively above, so my comments will focus on the bottom line, which I see as....
Power corrupts, and absolute power corrupts absolutely.
That's how I see Apple these days. As individual people I'm sure Apple employees are as cool as anyone else. But the company as a whole has reached a scale of success which predictably breeds bulk blindness, arrogance and sloppiness in any collection of human beings. As your grandpa might say, they've simply gotten too big for their britches.
In fairness to Apple, this syndrome would probably happen to just about anyone to experience that level of success. I sold a small tech startup once to a larger company, and it kinda happened to me. Even as just one little guy on a very big stage, I sorta started thinking I was really hot #$%^^.
I haven't purchased anything from Apple in 16 years, and don't use the Mac App Store unless the app is question is important to me and there is no other option.
To me, Apple is the personality of Steve Jobs blown up to enormous proportions. Truly gifted designers, absolutely brilliant marketers, and not very nice people (as a company). I don't hate'em, but I do try to avoid'em as much as possible.