I don’t think that they ever switched. They were always like this, they just managed to keep most people from realizing it. For one thing many of them were part of the Bush administrations and a lot of conservatives foolishly equate GOP with conservative.
Paleocons were wise to these power grubbing weasels as far back as the ‘80s. A lot of these NeverTrump goons are too young to have been part of that but the faction that they belong to isn’t.