Hmm, I don’t know about everywhere, but our local Cleveland Tabletop RPG group is actively doing something about this. We are convincing DM’s to make their games public. We have a public set of D&D one shots once a month and we are launching a general course on GM’ing 101 that is system neutral. Additionally we offering a apprenticeship program for new DM’s. Anyone could do this, but it is quite a bit of work.