More than half. Remember that 3 million more people did not vote for Trump than did.
Mmm. Honestly, depends how much one includes the non-voters and how. Non-voters made up, what, nearly 40% of the voting-eligible population?
A few weeks ago, when it became obvious that we were way behind in testing, I was noting to my wife that when she and I were growing up, the United States really was the top of the world. That wasn't propaganda. We had the best schools. We had the best scientists. We had the best health care. That was not a lie, back then. I expressed pity that that had changed, and wondered aloud what had gone wrong.
She responded, "Because people like Trump."
I said, "I don't think it's just Trump. This took a long time."
And she explained, "I didn't say because OF people like Trump. It's because people like Trump." She went on to explain that we have become a nation that demands easy answers, that demands to be taken care of, and that is all too willing to blame anyone but ourselves for our problems. That is exactly what Trump does.
So now Trump is up there tweeting that we will win! Yay! U S A!
And people, at least a lot of them, are eating it up.
Mmm. I'm going to call that an oversimplified answer, too, personally, and a bit misdirected. The easy answers one is defensible, but not particularly deep diving. The "demands to be taken care of" and "too willing to blame anyone but ourselves" is part of the right-wing narratives that played a significant underlying role in
causing exactly the problems that you're observing as they were weaponized to redirect blame from where fault actually rested. That's not to say that it's all the right-wing's fault - it's not. The factors in play are much more complex than that, though it's well worth paying special note to the way that rich libertarians have worked very hard for a long time to undermine and corrupt the government, specifically because the government has power over them and has been using it to prevent them from maximizing their profits by doing things like making their employees into slaves, whether directly or effectively. That actually has philosophical roots from well before the Civil War, incidentally, as the plantation owners in the South engaged in perhaps the most profitable endeavor in history at that time, creating an extremely unequal distribution of wealth and power that's left a very long-lasting and usually poorly understood scar in the US social and power structures and development. Also of note are the anti-science folks who the right has pointedly worked to court. With regards to a number of religions, science has both knocked down cherished tale after cherished tale after cherished tale as untrue and offers up a dramatically more provably trustworthy methodology to find answers than the religions offer. People with a vested interest in the continued survival of their religions, especially the people with a financial vested interest or an overt interest in scamming people like the prosperity gospel leaders and televangelists, have invested quite a bit of time and effort into undermining and attacking science and, well, education in general.
During the Civil Rights movement, especially, part of the political realignment that happened involved the Republican Party pointedly courting the anti-science religion leaders, and after the realignment, that group held a disproportionate say in the propaganda and direction of the GOP, which naturally meant that the GOP became much more overtly hostile to science when science determined that things that they didn't like actually are the case, and it's shown. The GOP's propaganda is one of the long-time significant influencers of how the US proceeds, of course.
There's much more that could be said, much of it less directly political, but... that's more than enough for now. Also, just to repeat a point that I barely touched on - Democrats aren't blameless by a long shot, however much the Democrats since, say, the Civil Rights movement are dramatically less at fault.