Based on voting demographics, the poorest are the ones who are voting for politicians who hate the government and are opposed to any kind of subsidized healthcare.
And it's not necessarily true among those who do vote either:
https://krugman.blogs.nytimes.com/2007/09/24/bubba-isnt-who-...
It's an old article and I don't doubt that 2016 has messed with the numbers, but the narrative of poor rednecks screwing themselves over every election is largely unfounded and smacks of classism.
It will take something like the union/wildcat teachers' strikes, that forced Republican majorities with unified control of state governments to raise wages and increase funding, to do anything about healthcare or the many other structural challenges we face as a nation.