There are multiple reasons for the doctor shortage but it's at least partly intentional. The primary bottleneck on producing new physicians is the number of residency program slots: every year some students graduate with an MD but are unable to practice medicine because they can't get matched to a residency slot (some do get matched the following year). Most residency programs are funded through Medicare and Congress has refused to significantly increase that budget for years. But here's the trick. By limiting the number of doctors they also hold down the cost of Medicare claims. If a Medicare beneficiary can't get an appointment because there are no doctors available then no claim will be generated and the federal government doesn't have to pay anything.

https://savegme.org/