Yuppies are generally trash, rich people can be economically progressive, but a lot of them don't vote for democrats for that reason, and wouldn't vote for an stedfast leftist, who cares about income redistribution, social welfare, and huge investments in poor areas aiming at helping poor people.
All suburbanites aren't rich, but generally suburbanites that swung to the democrats in recent years, especially to clinton, are upper-middle class and rich.
Also WTF on genocide.
"Yuppie" is a stupid word. Generalizing people as trash based on income is stupid at best. Many rich people currently vote based on themselves, but that isn't a hard rule. This dislike of the democratic party's trend in voterbase seems based on a tribalistic dislike of "yuppies".
Also the genocide comment was a reference to the trump wing of the republicans, which would basically run the party in the scenario described. Perhaps a bit hyperbolic.
Yuppies are not just rich people, their effects on cities and urban development has been disastrous, the dislike of the trend of the democratic party, is that we no longer represent poor, trash white working class communities in cities and rural areas, but instead we get the votes of upper-middle class people, who are in many cases economic centrists, with no desire of a reformation of society to help the working class.
Poor blacks and african americans still vote democratic, as they are threatened by the racism of the republican party, that whites aren't, which is good, but alongside that, we should still be getting the votes of poor whites, who had been democratic voters (outside of the south) for so long.