This is true, but large miners also have beneficial electricity contracts and data center capacity, both suitable for AI workloads.

"don't work well for AI" is a hell of an understatement, the Application they are Specific to is literally just sha256(sha256(x)), what AI are you going to do with that?

GP probably didn't mean that hardware though, but rather the facility, electricity supply, cooling, etc.

Why double sha256?

a that’s the botcoin hashing algorithm.

I figured that part out, I wonder why it's being doubled.

That was the way satoshi wanted it. No other explanation is known.

The disappointing truth is that we simply don't know. Satoshi never explained it. For SHA-2 it can be used as a mitigation against length-extension attacks¹, and this seems like the most likely explanation, but it's just speculation.

¹ https://en.wikipedia.org/wiki/Length_extension_attack

Would length extension impact bitcoin? The messages aren’t secret afaik.