Yet another reason that Iowa really doesn't matter.

As I said before, there is a non-zero chance that Trump will die or be completely incapacitated before the general election, allowing someone else to slip in as the Republican nominee, at least until Trump announces his VP.

That fact is the only thing that explains why DeSantis and Haley are running. Trump trouncing them both in Iowa doesn't change that fact at all. The opening could still come. Unless they run out of money entirely, they might as well stay in the race, at least until Trump announces his VP (because once a VP is announced, that person would presumably be deemed Trump's successor if something happens to him).