I think this comment is part of the issue.
I'm not American but lived and worked there. I was there on Trump election night and flicked between CNN and Fox, not quite sure what to believe.
In some States/places (particularly where there's a lot of poverty) there can be a feeling they've been forgotten, that the rich white men in the beautiful White House have zero idea of what it's like to live in Michigan or rural wherever. Many have lost everything but it doesn't feel like anyone actually cares.
Mix into that a culture deeply tied into Amendment rights/Christian values etc and well, it was a bush fire just waiting to be lit. Trump was far more strategic in his campaigning too. Despite being a rich white man himself he portrayed himself as 'self made', anti regulation AND he went on the campaign trail to places Clinton did not.
He spoke their language. And the more that people on the Internet branded his supporters 'dim', (see above) the more the movement grew.
In a bizarrely tone deaf move, Clinton doubled down by seeking endorsements from other rich people in Hollywood and Washington...the other 'out of touch' people. The media went massively OTT with its comedy shows and Trump's pretend decapitated head, branding him as 'Hitler'. He is many things but he's not a genocidal maniac who's sending millions to death camps.
I'm not a Trump supporter (I'm not a Biden supporter either!) but I work in strategy so I see how the campaign was cleverly designed and how it created a movement. I can also see the fatal mis-steps of Clinton and now Biden.
I don't know if he will get in again but I can see the same strategy at work.