The cost-shifting that results from the unfunded mandate to treat everybody who shows up at the ER only works if you have enough paying customers. In cases where they didn't, it has lead to some ER closures. Some states and local governments have also tried to help cover it where the alternative is closure.

This is one of the broken parts of American Health Care. It badly distorts the market because the paying customers consist of insured (who have negotiated discounts) and the uninsured cash-payers (who get screwed to cover all the indigent costs). It is thus impractical to self-insure, since your prices will be double or triple the costs of the insured for the very same procedures and items. Getting everybody covered by a health insurance policy would fix it.