That’s how it always worked in the days before the ACA. If you couldn’t afford health insurance, you waited until you had a condition that could not be ignored (for example, a heart attack), and you could get treatment at your closest ER (as they were required by law to treat you). Of course, all that ER would do is save your life, perform any surgery you need on an immediate basis (stents, bypass, etc.), and send you on your way. No follow-up care, unless you either had insurance to pay for it, or you could afford to pay out of pocket for it.
Even so, you could easily rack up a bill well into the six figures. And if you couldn’t pay, you’d declare bankruptcy. Of course, that still left an unpaid bill the hospital would have to worry about. The hospital could sometimes get partial compensation from the government through uncompensated care funds and pools, but the rest of the shortfall had to be made up through increasing the fees for those who could pay their bills — the insured. Higher fees = higher insurance claims, higher insurance claims = higher insurance premiums, higher insurance premiums = fewer people who can afford insurance. Fewer people who can afford insurance = greater frequency of this kind of scenario occurring. That’s right — whenever someone can’t afford to pay their hospital bill, the rest of us pay for it, either through our taxes or through higher insurance premiums.
Worth noting — this only helps a poor person with an emergent condition that can be taken care of in an ER, such as a heart attack. If the poor person has cancer, he’s SOL.
Which is why we want to have everyone insured (or as many people as possible). It’s cheaper to keep people healthy in the long run. However, we have way too many Republicans anxious to go back to the old days, when health insurance was a luxury for the rich and the ER was pretty much what was available to the poor.