You can't say that.I'm sure they are but I highly doubt it. As a matter of fact, I will add, Trump would be decimated in a general election.
If you get a major party nomination, you basically have a floor and especially due to the deformations of the American system, you always have a shot at winning.
In the current negative polarization environment, that's just the way it is.
Add in the fact that people will react to external shocks in all kinds of silly ways, you can never guarantee Trump (or anyone else) would be decimated this far out. (A collapse much closer to actual election day is different.)
There are thin margins in a presidential election, even if Biden wins by even more votes than last time.
You just need a few breaks in the right way, and Trump can win even if most of the country doesn't want him.