I think for a lot of these wealthy Republican suburban counties it's either 2020 or not in the forseeable future. It's hard to find a Republican more toxic to wealthy conservatives than Trump. Even if they nominate Cotton or so he'll definitely do better than Trump with wealthy voters. Romney won people earning over 100k 54-44 while losing 51-47 overall. GWB outperformed similarly with wealthy voters (58-41 with wealthy voters vs 51-48 with the general electorate). If the Republicans nominate Pence or Cotton (which is a big if though) in 2024 wealthy voters probably will go back to the Republicans, especially if the Democratic incumbent is someone like Warren or Sanders.
More* wealthy voters will go back to the Republicans. Let us not forget that the exit polls looked like this in literally the tailor made matchup for wealthy voters to vote Democrat and many less wealthy voters to vote Republican:
Under $30k: 53% DEM, 41% GOP
$30k-$50k: 51% DEM, 42% GOP
$50k-$100k: 50% GOP, 46% DEM
$100k-$199k: 48% GOP, 47% DEM
$200k-$250k: 49% GOP, 48% DEM
Over $250k: 48% GOP, 48% DEM
Well, scoring 48% of the wealthy voters in a two-party system is really pathetic for a right-wing party (but then again, Trump did much better with less wealthy voters), and even candidates like Romney or Bush did relatively bad with wealthy voters compared to European right-wing parties. Most European countries have more than 2 big political parties, but if you add up all parties that are considered right-of-centre I think the European right scores better with wealthy voters (and worse with working/middle-class voters) than the American right.
But Trump probably is one of the few Western right-wing populists whose voters are wealthier than the average voter (maybe the Progress Party in Norway or the Swiss People's Party in Switzerland also have relatively wealthy voter bases? I'm not really an expert on these countries
). But if you only count the diehard core Trump supporters that would also vote for him in a parliamentary PR system I'm not sure whether his base is much different from the average right-wing populist party.
