That's a fundamental shift in historical Republicanism though.
For most of its history, the Republican party was fairly anti-populist (defined by whatever populism was at the time).
The Republican southern strategy from 1980+ was predicated on attracting southern white votes by attacking civil rights (explicitly or implicitly), but ultimately focusing on business priorities (with some headline-catching red meat).
However, in the decades since, the explosion of hardline conservative talk radio then dragged the party to answer to its more egregious populist demands.
I would argue that their opposition to civil rights was populist. It was amoral and intended only to get votes from racists, as an “ends justify the means” way to pursue deregulation and corporatism.
That bait-and-switch reveals the core, though. The R base wanted what Trump is doing all along but was tricked by the establishment business class. The reason they are so loyal to Trump is because he ripped away the fasaud and acts out their longstanding wishes.
For most of its history, the Republican party was fairly anti-populist (defined by whatever populism was at the time).
The Republican southern strategy from 1980+ was predicated on attracting southern white votes by attacking civil rights (explicitly or implicitly), but ultimately focusing on business priorities (with some headline-catching red meat).
However, in the decades since, the explosion of hardline conservative talk radio then dragged the party to answer to its more egregious populist demands.
Hence Trump.