They have a first past the post parliamentary system, derived from the UK. The US has a separation of powers between its executive branch and its legislative branch.
The way to build third parties is by reforming the democratic system state by state to have a ranked choice system open non-partisan primary to select the top two final candidates followed by a general election between these two candidates for each election to elect a representative or president.
It helps mitigate the flaws of the ranked choice system to have it stop at the final two and let the voters choose between these final two choices. It helps get candidates that are at the center of voter opinion distribution.
This means the hard work of mobilizing together and working across partisan lines, recruiting the majority of Americans that are pro-democracy in each and every state.
It’s mostly the color of the light that’s the problem right? Our brains register the cooler light in the contrasting darkness as blindingly bright as opposed to warmer incandescent light, despite both lights having the same measured brightness (lumens).