It defintely will crash and burn. Okay at least crash an never revisit those highs, remeber that we have has similar situations with bitcoin cash and btc.. the eth fees will go down and the bsc will lose its relavency.
It seems that the BSC will not just disappear when ETH costs have decreased and stabilized at a low rate, because they are basically on a different path so that investors and new project developers can make the choice of which one they will choose for their business.
I think so too, BSC has been building its own ecosystem this past year quite well so many dapps released in there and also defi but you see the main reason why people switching over to BSC because the whole blockchain was meant to be alternative and it's not impossible that many people gonna go back again.
Though, never underestimate the power of an exchange that dominates like crypto market around the world, they could make a project that was initially not popular become so popular it got pumped thousands of percent once gets out to public and available for trade, pretty sure they can keep BSC alive aswell.