The Dumbening of the Mobile Web

I appreciate that websites are developing specific front-ends for mobile device access. As an iPhone owner, I appreciate the iPhone specific front-ends that websites like Twitter, Facebook, and Google Reader have created. However, why are all these mobile versions dumbed down to the point that, beyond the most simple, basic functions, I have to revert back to the standard site to do anything?

Particularly with the iPhone, my browser capabilities aren't neutered, I just need things delivered in smaller, bite-sized chunks. The mobile versions of these sites are not as useful as they could be because, instead of repositioning many of their options, they've just removed them. Boo, I say, boo!