This is the sort of thing I'm worried about. But don't miners make a profit mining with their GPU rigs now? Why wouldn't ASIC rigs make money once all of this levels out? When the difficulty goes up, wont the value of BTC change to reflect that?
GPU are quite dead now. They cost more in electricity than the profits they can generate.. And with ASIC coming, it's really going to be the end for GPU soon.
Difficulty and value does not affect each other. In one line : The difficulty is the competition between miners, while the value is the competition between buyers.
A very high hash rate does not mean more people will want to buy and use Bitcoin.