Why wouldn't it happen? If enough consensus raises, anything can happen.
If PoW becomes unsustainable, I am pretty sure PoS will be the next step but that's one big if.
It is like saying "if enough consensus gathers we will censor bitcoin"!
There are certain principles in bitcoin that will never change, one of the most important ones is security which will be removed if PoS replaces PoW.
All you could say is that if PoW becomes problematic a new but better algorithm will replace it but it definitely won't be PoS.
The migration of miners from China mainly to the US
I still haven't seen any proof of this apart from what the news sites said and a single study with unverifiable data. I'm not saying this is or isn't true, but we simply have no evidence.
it was because of a political issue.
US isn't so friendly to bitcoin either. I'm sure that if it continues to grow and specially start threatening US dollar they will start cracking down hard.
Since then, the price of energy there has been rising in the US. I suppose some will be considering going elsewhere if it continues to rise, but there are many factors to take into account:
It wasn't since then though. US and Europe have been having some energy problems and with increasing gas prices the electricity cost has been rising for some time now.
In fact this is one of many reasons why I have trouble believing that Chinese miners moved from Asia (that has a lot of countries with super cheap electricity and friendly to bitcoin) to US (that has higher electricity price that is increasing and is not as positive towards bitcoin).
When the miners left China many had to sell Bitcoins they had been holding and there was a downturn in the market.
Nobody "had to" sell bitcoin, they panic sold which is part of market manipulation that happens every now and then for different reasons!