They used to do that. In the Apple Store video Steve put together, he explained that the geniuses would be well trained Mac technicians that could fix most anything, and when they couldn’t, there was a phone they could pick up to talk to a engineer at HQ.

Now, due to cost (although price has gone up for the stuff), the Geniuses are no longer trained at HQ, and there are now lower level “technicians” that can’t do much more than give you a new phone.