But, and I think this is key, they -aren’t- being betrayed. In the past, the political parties made promises that they’d provide jobs, lower taxes, safety, etc. And most often, they didn’t even try, or tried and failed, or barely moved the needle.
The ‘genius’ of Trump and those who follow in his wake is to not promise those things. They promise that they’ll HURT the people they dislike - immigrants, LGBQT+, non-Christians, THE THEM of all types and flavors.
And in this, they succeed. And they love him for it. The fact that they are being fleeced, that they aren’t improving their lives, and in fact are demonstrably losing opportunities (jobs, education, etc) DOESN’T matter.
As for what happens if Trump wins, I think that Trump will spend his time gutting every single Federal agency, and will succeed. That in and of itself will fundamentally crash our government as we lose everyone with experience and competence. The states will more or less go their own way in the meantime, until we fail to raise the debt limit next time… and when things get bad enough, he’ll declare martial law for the duration.
After that? Well, it’s an ability the executive has, the legislature (R) is craven, and the SCOTUS if they remain strict structuralists, will demure. And then, THEN it’ll get bad.