You don't get it. The government limits the amount of residency spots. They fund the residency spots. And most students do not pay upfront, they go into debt to fund their education. Having students pay more or go more into debt will do nothing. The amount of residency spots is ultimately determined by the US govt
This is factually incorrect the US government pays for a fixed number of slots, but they don't pay for 100% of the residency slots available. Thus there is no legal limit on slots.