I was wondering the other day: where are the iPhone-compatibles? When the PC industry took off, it was because some hardware guys bought some off-the-shelf components and started building desktop computers compatible with IBM configurations for a fraction of the cost. I guess what's standing in the way of the same kind of action for iPhones is proprietary everything in a tiny, well-engineered package. That doesn't mean you can't get a knock-off lookalike from a Chinese sweatshop, but I'll bet it won't run anything from the App Store or last even a third as long as the real deal.
And if someone legitimately tried to make a compatible non-iPhone, Apple would stomp them to the ground with a titanium sledgehammer of lawsuits before they even got to packaging the thing. Like it or not, Apple has taken over the smartphone space just like they took over portable music. There's not much hope of prying their iTunes claws out of music until DRM-free sales are the norm and it's easier to sync with any random player, but if another touch-screen smartphone ran App Store content, cost less and was otherwise indistinguishable, Apple's market share would start to shrink.
Mokalus of Borg
PS - Then again, it might make that whole App Store ecosystem less attractive.
PPS - Because then you'd never be quite sure which apps would run on your phone.