Because as a society we know it’s cheaper to treat early and often rather than deal with emergencies 80% of the time.
Also, I agree with you, but likely from a different place. No individual should be paying a hospital bill, it should be included in a tax on my income. If I have lots of income I pay for lots of people, maybe an astounding amount, if I have little to no income I depend on my wealthy neighbors to cover me. Seems to me like the only way to go, that or I guess the rich get eaten.