Polticians hate populism, it’s govenement for the people, rather than for the politicians. So, whenever populism pops up, in any party, the politicians fall all over themselves to try ro stomp it out.
The other matter is corporatism. The pubs used to be for corporations, while the dems were for grass-level graft.
Now that the Dems have fully embraced corporatism, there is no use for the “old” Republican party, but the ‘pub red meat of being for America and patriotism created a space for Trump’s populism to take hold.
And since nature abhors a vaccuum, take off it did.
I teach at a major university. Political science is the major that attracts the “easy A” types who want to rule us all. Republicans are just milder Democrats, but still want to rule us and share in the spoils (government spending and regulation). In other words, you shouldn’t trust any politician. Usually Republicans are less toxic than Democrats, but toxic none the less.