If this is happening now, why would they cut the number of doctors?

They can't sell the debt for uninsured non-emergent case for enough money to cover the doctor.

Cutting doctors means only the most prioritized triage cases makes it to doctors, which skews towards people that are employed or on medicare and the money can be recouped, and thus improves profitability.

It's an end-run against the requirement they take in the hordes of people with no insurance who show up to the ER for low-income cases and no way to pay it.

If doctors were so cheap as to be covered by the sales to debt collectors, the whole thing gets flipped, as it would be profitable to just hire armies of them to cover the hordes who come in with non-emergent cases.