The social democracy I am describing in my arguments would do away with capitalism but not market economies. The fact this doesn't exist yet or isn't in the theory you have read about social democracy isn't relevant. The US has never had true majority rule. Our democracy overrepresents some people and thus underrepresents others. This must be fixed. The US is still fundamentally a democracy despite its flaws. That's why the fascists want to do away with our democracy, so they can have total power, as just being overrepresented is insufficient for their aims.