> You seem to be under the impression that the large blocks of voters actually understand and care about the issues. Large corporations and their considerable advertising and lobbying efforts are what's really important. Much of this effort is to frame issues to the public in the way they choose.
The idea that it's the voters that vote is actually true! That's how the system works. Corporations can influence that of course, probably to an enormous degree. But the corporations themselves don't vote. That's the system we've got.
The primary mechanism in our system is people. And people aren't logical, rational, economically-maximizing, or any of it. People are far more narrative-driven than they are rationally-driven.
THAT's what I would say that Republicans would get on board with a universal healthcare bill in which they could claim that they "destroyed" the Democrats by "obliterating" a bunch of "socialist pork". But that's absolutely going to ensure that the Democrats that "caved" in order to get something important done won't be able to get re-elected. And they care more about getting re-elected than they do about doing the right thing! Same on the other side of the isle! This isn't a partisan issue. Everyone wants to get re-elected way, way, way more badly than they want to do the right thing.
I don't like it. I don't think it's right. But it's extremely easy to see that neither party is compromising in any meaningful way these days. Both take hardline stances and don't budge. That's not a bug, it's a feature of American Democracy. It was designed such that if there wasn't wide agreement (or elected officials who would compromise) that things would grind to a halt. That was done so that nobody could run roughshod over the other.
Until we start getting richer such that the increases in spending are coming out of even bigger growth or we somehow manage to convince everyone that paying more and getting less is totally-A-OK this is going to be how it continues to go. Neither side wants to compromise, so their counterparties don't want to either. Deadlock is the name of the game.
> and they actively vote against their own best interests
I can understand how you'd think that. It makes a lot of sense. But it belies a terrible ignorance on your part. Animals don't make decisions on purpose to make their own lives worse in ways in which they KNOW they will end up worse. You can try and project your ethics onto other people all you want and use their relative-to-you irrationality to belittle them. But it doesn't work! Putting people down doesn't change minds. In fact putting people down might be the very thing that got Trump elected (re: deplorables).
I'm not saying Trump is good and Hilary is bad BTW. I'm just using that as an example of how unfortunate it can be to generalize one's personal ethics to the entire country and draw conclusions as a result.