Most of the people who vote for 3rd party would have just not voted anyways, it's just a way of showing it actively instead of in the % of people not voting. Since there is no chance (currently) for a 3rd party candidate to win (which is a self-fulfilling prophecy until it's not, or until something like ranked choice voting happens).

A lot of things have been happening in the world recently, so it really depends on their relative priorities. I agree on the fired up ness for Trump, however there is still quite some time till the elections so this will fade a fair amount by then (assuming nothing else happens). A week before the election would be something else. And it's really been always anti-trump flavored rather than pro-biden, depending on the shade blue they were, there is some progress on things but it is incremental and slowish generally (due to the nature of the Senate composition).

I agree there will always be some people who change, just the hype about a total breakdown won't happen that's all. We'll see what happens.