Keep in mind that US elections are generally between 2 candidates acceptable to the existing power structure, with a sideshow of more novel/progressive/interesting candidates who can't win because it's set up to be almost structurally impossible for them to.

I would be the first person to agree with you.

How do we fix it :-/ I think a proportional voting system would open it up, but that conversation is so far from the one we have on the national stage that it seems ludicrous.

I don't know, it's so completely complicated. I would think we'd have to move to a parliamentary system to really break the duopoly. The media demonizes and marginalizes any other political parties in America, and Americans want to be "winners" so some even vote for a party based only on the perception that they will be the triumphant side.

The problem is that it seems like for most people, choosing between a few options is preferable than to have to carefully examine and choose from a wider array.