If you are expecting AI to not have much impact and turn out to be a bubble, then I guess there isn't much reason to believe it it will have much environmental impact. If you expect AI to not be a fad, then yeah it could have big environmental consequences if we can't find renewable power and coolant. If AI is all it is hyped up to be, then it would dwarf the rest of humanity's power consumption down to a footnote. So it really depends on how bullish you are about AI, or at least how bullish you expect the market to be going forward.
Regarding proof-of-work crypto, well, bitcoin is currently at its all-time high in terms of value, exceeding USD$100k/BTC. So I'm not sure I exactly buy the idea that it's less popular, though perhaps people aren't reporting on it as much. If the power consumption of crypto has levelled off, which I don't know if it has, then it might be because it's expensive to build a mining rig and the yield goes down over time as more bitcoin is mined. (It's presumably true of other proof-of-work crypto, too, but as more BTC is mined, the marginal yield of mining more BTC decreases.)