Not an expert but it seems to me the most important thing is education. In the U.S. they’ve been chipping away at that since at least the eighties. I’m not “handing it to them” but the right has put in the long term work to get us where we are today, with only feeble liberal centrist pushback.
I’m sure you’re correct. Just as a poor education along with lack of socio-economic opportunity and inavailability of mental healthcare might contribute to radicalization in the working poor, it stands to reason that a basic lack of empathy, whether taught or innate, likely coupled with greed must play a role for radicalization of the wealthy.