I disagree on your presumption of the political make-up of the independent vote. I think they are actually more progressive, as proven by how well Bernie Sanders polled among Independents — this is why he always led Trump by close to double digits in 2016. When you examine the polls of voters on issues, their beliefs also come down on the side of Sanders.

What we have in America is control politics, largely due to the money influences coupled with political operatives gaming the system and tweaking the demographics by means of voter suppression tactics and use of propaganda tools. Also throw in some dirty tricks!

When all is said and done, since JFK was shot, America has been led by center-rightwing politics, with the center coming in to clean up the rightwing mess. Progressives voices have strategically been locked out.