Answering your questions-
I have been a PD for nearly two decades (two programs) and expanded a program once-in 1999 I believe (from 6 to 8).
I am no longer a PD but refused to expand the second program I led in the last five years despite faculty and resident requests to do so.
If asked I tell everyone that we are training too many people and that this is a very bad thing on several levels. The only stakeholder that wins in the too many doctors, not enough patients scenario is the hospital. Tragedy of the commons comes to Radiation Oncology.
I have no position of power; the hospitals and payors have all of the power and money.