You are fundamentally misunderstanding the purpose of the difficult mining in Bitcoin. It is to keep the currency scarce and difficult to obtain. If it didn’t scale with increases in technology all the Bitcoin would quickly be mined and you’d have money printing like the fiat money we are trying to escape.
With AI, on the other hand, efficiencies help. Of someone comes up with AI hardware that does inference or training 10x more efficiently, people will incorporate that and the energy usage for the same amount of work will decrease.