Bob Dole (the Republican presidential candidate in 1996 who ran unsuccessfully against incumbent President Bill Clinton) made a comment about the U.S. healthcare industry during that 1996 campaign. His advice was simple --- "Don't get sick!".
Sadly, that attitude seems to sum up the U.S. market for healthcare, at least prior to the Affordable Care Act (pre-Obamacare), and with respect to the uninsured. If you had a preexisting condition, a low-paying or part-time job without benefits, were self-employed, etc., access to affordable healthcare was difficult and often impossible. As a result, it was estimated that 47 million employed, nonelderly Americans (i.e., approximately one-third of all U.S. workers) did not have medical coverage in 2012.