It may boggle the tech-savvy mind, but another way of reading the incredibly successful 10 year history of this horribly locked-down, oppressive OS is that the market has spoken. And it's happy.
Don't forget that the market was pushed that way by Apple's highly influential marketing. People didn't really choose to give up their freedom of their own free will --- they were persuaded to, and only found out about the downsides afterwards.