Rich upper-class white people are still absolutely a republican demographic, if there's any rich people the democrats woo it's highly educated wealthy people, urban wealthy people, and wealthy people who are minorities of some sort. Whereas your prototypical rich republican is a WASP who owns something like a mining company and lives on a ranch or something.

The democrats also notably have a lot of support among the poorest in society, and this base is a LOT of their electorate, so this really shouldn't be overlooked.