Let's all be honest. The shortage is in underserved areas and to more accurate, in underserved rural areas. The pay usually isn't that great and more often then not they're places people don't want to live and raise families, so there is a shortage of physicians, usually specialist. In the cities or near cities anesthesiologists are falling off trees, so in that case it become supply vs demand. There are so many around that we can pay them crap (NYC, SoCal, etc)
In the rural areas they're fighting low supply combined with poor payor mixes/mostly medicare, medicaid that also contribute to no one wanting to go work there.