Some employers put a limit on how much you pay out of pocket, even below the maximum amount of pocket required by the ACA, almost, but not quite comparable to what you get in countries with socialized medicine or health insurance systems. They essentially assure that medical treatment can't bankrupt you.
Obviously, most people in the US don't have access to such a generous plan, or the amount of medical expenses they can tolerate without going into bankruptcy is below the legal out of pocket maximum (6k/yr individual, 12k/yr family). Hence the GoFundMe pages to raise money for medical treatment.
There was a somewhat common misconception that the limit was per person, not per policy.
Although, the distinction wasn't very meaningful because you could be denied for pre-existing conditions, so if you had hit a lifetime limit on one policy, good luck being able to get another one anywhere else.
