Eh, I wouldn't say it 'evaporates'. These are people who don't like the job either party has done but certainly think one party has done a much worse job. Which they would never vote for.

So they're not going to change parties but they are hungry for a new party (or a significant change in an existing party).

I'd describe it as a political powder keg waiting to blow if the right forces are applied to it. In a word its discontent, people who's interests are not being represented by the political process.

You could say Trump tapped into that discontent a bit by appealing to the ones who think the parties aren't racist enough against immigrants.

He didn't dispense with the energy because the things he said were problems are largely figments of the racists imagination. So now some immigrants are dead or in concentration camps and those racists are no better off.

DSA is also trying to tap into that energy. Time will tell if they can wield it to become an enduring force in American politics.

Last time there was a powder keg like this that went off FDR was the one that lit the fuse and he won 4 terms. The establishment hated him so much they passed term limits.

That's what it looks like when someone successfully taps into it in a way that actually resolves the material problems in peoples lives.