I'm going to suggest that it wasn't human nature that changed. Ie, the elites are not better or worse today than they have ever been as human beings

My real answer is that 40 years of low interest rates, have shifted all power to capital (not capital as a group of human beings. to literal capital) and now the workers are mad at a system setup to screw them and scapegoating the people on the other side of that system who really aren't the ones who set this up either.

It's an important question to think about. What changed from the Silicon Valley of old that believed anyone could accomplish anything - someone in their garage could change the world - and harnassing that enormous talent and ideas was their mission.

IMHO, they seem to be following the reactionary culture that dominates the US now - the worship of power, the contempt for humanity, for humans, and for the future.