tl;dr: American ambulance bills are extreme because a 1965 Medicare decision treats ambulance service as a per-ride procedure, but modern EMS costs are almost entirely fixed—paying crews and vehicles to stand ready 24/7. Since Medicare, Medicaid, and the uninsured all pay below cost, and insurers have no incentive to go in-network (ambulances can't steer patients), providers recover their costs via massive out-of-network surprise bills to the privately insured. The fix is funding readiness like an option—via taxes or premiums—as other wealthy countries do.