People were blaming cryptocurrencies miners for the prices of GPUs, when in fact it was the AI researchers who bought all the GPUs. :D
I wonder what if somebody designs an electronic currency rewarded as payment for general GPU computations instead of just computing hashes? You pay some $, to train your model and the miner gets some coins.
Every one is happy, electricity is not wasted and the GPUs gets used for a reasonable purpose.
Yes, this is an old idea (which I really like) but it hasn't really taken off yet. GridCoin was one example, where you solved BOINC problems or RLC that's for more general computation.
The problem is that, currently, large ML models need to be trained on clusters of tightly-connected GPUs/accelerators. So it's kinda useless having a bunch of GPUs spread all over the world with huge latency and low bandwidth between them. That may change though - there are people working on it: https://github.com/learning-at-home/hivemind