Bitcoin doesn't even need the huge ASIC farms that exist today. The difficulty right now is way overkill.

Honestly, I think it would be a good think if a bunch of ASIC farms were forced into shutting down because of falling profits. Bitcoin can function perfectly well without them. With USB ASIC miners available at $5, there's always going to be a low barrier option available to enthusiasts who can support the network on their own if professional mining becomes unprofitable.