Ultimately there are not hard-coded rules saying a progressive vote is worth less than a conservative one

There might not be rules explicitly for this purpose, but the Electoral College and Senate are hard-coded institutions in the US government that effectively guarantee this. The antagonism there is more framed as a rural vs urban one, but it effectively amounts to the same thing in practice. Going by Wikipedia numbers, every elector for NY represents the votes of up to 714,372 residents of New York, while in Wyoming, that ration is considerably lower, at 1 elector for every 196,251 residents. This ignores things like residents counted in the population who are ineligible to vote and people who just don't, but you get the point. Ditto for the Senate, where some 10 million New Yorkers get the same representation as just under 300,000 people in Wyoming.

Yes, rural states could eventually swing left again and make this no longer the case, but it certainly seems unlikely at any time in the near future.