If you were to intentionally try to make a collision, it would currently take 2^126 times longer to generate a colliding bitcoin address than to generate a block. You could have got a lot more money by generating blocks.
What if your network of computers already generated and tested all the possible blocks?
Sure the address haystack of possibilities is much bigger and harder to test... but if the other haystack(block generating) has bean fully counted what else is there to do?
This is sillier than asking what happens after all the atoms have been examined. Nothing, nothing happens. Even if you could look at the entire space eventually (you cannot, one trillion of you cannot) you can't remember it either.