They exist becaude the government has created rules to try to force health insurance to be a national health system: companies are encouraged or forced to buy i

They exist becaude the government has created rules to try to force health insurance to be a national health system: companies are encouraged or forced to buy insurance for employees, the healthy are forced to subsidize the sick and elderly, and insurance must cover most treatments. There are other non-insurance interventions like forcing hospitals to provide emergency care.