>The principled intellectual wing of the US conservative movement has virtually disappeared.

I see similar on the left. You see a lot of people who had good things to say marginalized because they pushed back against the current populism or people who should know better embracing it so save their own hide (my senator being one of the latter).

Anti-intellectualism is part of populism, I would guess, and currently the Republican Party has been overrun with populists. There are certainly never trumpers talking about the older conservative values, but they are in the minority.

Things will change. They always do.