Insurance/Pharmaceutical companies are heavily involved in lobbying so that politicians vote for legislation which favors their profits and veto potential legislation viewed as a threat to their profits
Many Americans in desperate need of healthcare have overlapping financial/job struggles which make prioritizing their healthcare difficult, let alone actively seeking it out or being involved in healthcare reform activism
A shitload of Americans lack the ability to vote for their own interests because they've been brainwashed into thinking any tax money not spent on national defense is "socialism"