Ideologically, just enough voters in the right places believe that unless you’re old, or a military veteran, in which case government healthcare is just fine, your sickness should not be their problem, even if it means they pay more for their own care.

Also, if healthcare wasn’t tied to having a job, then the inherent laziness and moral degeneracy of people without jobs would be encouraged by letting them not be sick. (BTW, being self-employed does not count as “having a job” in this mindset.)