Maybe there will be a PoW coin that will become in demand? Isn't that basically how Ethereum got popular?
No, Ethereum was an innovation over Bitcoin. Bitcoin is 'just' a decentralized ledger where changes to the ledger are approved by miners.
Ethereum added a standardized way to negotiate and store contracts, which is why things like NFTs and crypto game assets are typically stored on the Ethereum network or a network using the Ethereum technology. In general, Ethereum is way more interesting due to its ability to be more than just a decentralized currency, as it can also support things like decentralized ownership of digital assets (which can in turn be linked to real assets, so you could decentralize all kinds of markets).
These two innovative and old crypto coins are way more desirable (and thus more expensive & traded much more) than more recent coins, even those that innovated with things like Proof of Stake. So this idea that people can just make a new coin and it will be in high demand is inconsistent with what happened so far and is likely to happen in the future. Even a big company like Facebook completely failed when they tried to introduce a new crypto coin.
The only reason why a new PoW coin would become popular is if there are many people who really prefer Proof of Work, but who would that be other than miners? They won't be able to afford mining long if they can only sell the coins to other miners, as mining will then always be something that costs miners money, as the only way for them to make money as a group is for non-miners to buy these coins.
Or if there is some amazingly innovative coin that people want to have and thereby manages to gain the trust of so many people that it is seen as an investable coin by more than just a fringe, which so far is only true for Bitcoin and Ethereum.
So unless Proof of Stake Ethereum is a disaster that causes people to lose trust and to prefer a Proof of Work offshoot of the current network (basically, taking the transaction history of the old network, but not trusting transactions approved by the Stakers, but only by miners on the offshoot network), I just see the GPU mining market sinking like a certain ship of war. Of the two popular coins, one will be mined on ASICs and the other will the PoS.