How? You need a residency to actually learn how to do stuff.
Just getting an MD is not enough to make someone ready to be a practicing physician.
Graduating more MDs doesn't automatically create more specialists tomorrow.
This is medicine. That short term pain means more people die than would have before.
When specialists quit, who replaces them? You need to be trained - just book learning and shadowing during an MD is not enough.
> everyone already in the industry needs to work even harder to do that
Everyone in the industry is already working hard.
The average physician works around a 50 hour weeks but 25% work 61-80 hour weeks [0].
It's already teetering on the brink due to burnout.
[0] - https://www.ama-assn.org/practice-management/physician-healt...
That said, I do think there's probably more of a role for some graduating med students than we use now. I don't think they need a 3-year residency to enable them for many general practitioner duties particularly in rural settings where the patient load is less, the pay is likely less, but the cases are more homogenous.