You have to remember that hashrate is fungible, just like electricity or Bitcoin. These three forms of energy (computation, power, storage) can be shifted around, to produce more of one and less of another, so long as the system stays energy-efficient.

If you have idle computation capabilities, and limitless energy, you can find a way to use that computation to convert that energy into Bitcoin. Even if you burn out the GPUs, after a couple of years, you can still make a lot of money with 1.3 million GPUs.

And, you would only be using any computation leftover from the AI stuff. If you shifted the mining computation from one GPU to another, they wouldn't burn out.