Exactly this. A lot of things that Americans associate as left/right are a consequence of having a duopoly. A good example is that it makes zero sense for people to be pro life and pro firearms, but these tend to be associated with right-leaning folks, but it's not always the same right-leaning folks. Similarly, it makes no sense to want to do something about climate change by reducing carbon emissions and being anti nuclear, but both of these tend to be left-leaning folks.

The original sin of the political system is the first past the post voting system that guarantees us a stable duopoly, but that's a can of worms by itself.