I've been browsing /pol/ for years, hell almost decades. Its a great place to go to get an idea of just how fringe certain elements of society are becoming. I was actually actively browsing when QAnon was making his posts there.
I thought they were just as ridiculous and far-fetched then as I do now. People become radicalized largely because some condition in their life is lacking. For every single successful mechanical engineer that joins ISIS, there's 99 out-of-work coal miners and factory workers who storm the American capital.
Most people who have everything in their life going great don't end up extremists.