Is there some legal obstacle to some entity other than Medicare funding it?
don't think many other entities besides the federal government have a ton of incentive to fund residency. and the federal government does have caps on residency slots
[1] https://slate.com/technology/2005/06/private-funding-for-res...
Interesting related thread: https://www.reddit.com/r/Residency/comments/a01cfr/funding_y...