It’s because the two-party system is a systemic problem. Our winner-take-all voting system always punishes similar candidates, so if similar groups don’t form a coalition and choose a single candidate to run for them, they will cannibalize each other and surely lose. So, you inevitably end up with two parties each representing all the factions on one side of the spectrum.
If we had a different voting system that did not punish similar candidates (like ranked choice), not only would quality third parties be possible, they would be inevitable.
It’s because the two-party system is a systemic problem. Our winner-take-all voting system always punishes similar candidates, so if similar groups don’t form a coalition and choose a single candidate to run for them, they will cannibalize each other and surely lose. So, you inevitably end up with two parties each representing all the factions on one side of the spectrum.
As a result, anybody on the national level who decides to run as a third party candidate (a) doesn’t understand our voting system, (b) is just doing it for the publicity, or © is out of their mind.
If we had a different voting system that did not punish similar candidates (like ranked choice), not only would quality third parties be possible, they would be inevitable.