I think you've got that backwards. Profitability doesn't go up until the difficulty adjusts. Once the difficulty adjusts, it's cheaper to mine each Bitcoin and

I think you've got that backwards. Profitability doesn't go up until the difficulty adjusts. Once the difficulty adjusts, it's cheaper to mine each Bitcoin and everyone who still has a rig running will make more money. The increased profits will continue until everyone who was displaced from China can find a new home, but this isn't going to be a quick process, Bitcoin requires enough datacenter space that all the Bitcoin-ready datacenters outside of China are already full!