Russia has nothing to trade that the West can do without. Sure, they foolishly tied themselves to Russian gas but that can be undone. Otherwise, what have they got? Absolutely nothing.
So in a scenario where you (in the medium term, at least) don't have to trade with the offending party, why woud you?
Sanctions are only partially something so transactional as regime change. Nobody in their right mind thinks sanctions = immediately the end of Putin. It is about sending a message that we don't want anything to do with you because of your actions. It may not be a deterrent, it may do nothing, but who really gives a shit. This is a principle.