> I think there'll be a massive increase in energy prices [...] which will make proof of work crypto unfeasible
Proof-of-work cryptocurrencies automatically adjust to use as much energy as possible (the amount of energy which can be bought with the block reward and fees acts as a cap, and the incentives are to increase the amount of energy used until reaching that point). If energy prices increase, they will adjust by using less energy. This has no effect on the block sizes or block intervals, so the feasibility or lack of it of any mainstream cryptocurrency will be unaffected.
Proof-of-work cryptocurrencies automatically adjust to use as much energy as possible (the amount of energy which can be bought with the block reward and fees acts as a cap, and the incentives are to increase the amount of energy used until reaching that point). If energy prices increase, they will adjust by using less energy. This has no effect on the block sizes or block intervals, so the feasibility or lack of it of any mainstream cryptocurrency will be unaffected.