There are multiple small parties, but the moderate bloc that likes to occupy the center of the US political system hasn't thrown in behind any of them because (it appears) swinging between the two large parties is more profitable. Like I said, if they really meant it they would
stake out territory.
I think it’s a legitimate pragmatic decision to try to influence from within one of the two parties.
So, sit in the middle and say 'both parties are too extreme' while bargaining with both for concessions and refusing to organize outside that framework, even though moderates/swing voters consider themselves to be the largest political bloc. That seems like perpetuating the system you complain about for profit, which is exactly what I complained about in the first place - a lack of any identifiable principle. You mention 'principles that the extremes of the parties don't prioritize.' What are they? Where are your red lines?
Moderates also tend to run as independent candidates. Ross Perot is probably best known in the US.
Ross Perot ran 30 years ago, since when we have been through two major wars, a huge financial crisis (and multiple smaller recessions), a pandemic, and a constitutional crisis. No outside candidate has mounted a serious challenge since then. Plus he was only able to do that because he was independently very wealthy.
I have posted this article about polarization here many times since it was published and all I ever hear from moderates is how bad it is, so bad that nobody can do anything about it. Moderates' unwillingness to anchor themselves to anything is a major contributor to the problem of polarization.
https://www.vox.com/2015/4/23/8485443/polarization-congress-...