Bitcoin mining companies have farms of ASIC miners which are designed to only do one job, to mine Bitcoin. How can they offer other cloud services? If they had GPU mining farms (which isn't profitable and as far as I know, everyone is on ASICs), then they would be able to rent their GPUs to AI labs and anyone who wants to use it for AI.
This mining companies are already switching to AI, it's worth for them to buy new hardware which they would have to buy anyway for Bitcoin.
No one is going to attack Bitcoin.
If the security drops, I will attack it.