Here in the UK we had a "2-party" system for decades with the 3rd party seen as a bit of a joke.
Over time however, the 2rd party system became a 3 party system, and today we have more parties in Parliament with a good number of independents.
Far from fixed, but change is possible.
If I could wave a magic wand, the first stone I'd lay in the US is to remove money from politics. That is the biggest corruptor of governance incl healthcare policy.
@rzeta0 I'd wish to remove professional politicians from politics, regardless of how many parties there are. A significant number of the population can smell these careerist phonies a mile away, and feel deprived of any semblance of direct democracy. Once we have that, we will be closer to freedom, not by choosing our masters from a wider selection.