[ChikkaChiChi]

I would try a subscription model similar to Spotify.

Let Bethesda charge 2 dollars a month for access to their workshop. Modders then get a piece of the kitty for the number of subscribers to their mod.

Quality would increase because modders would want more subscribers, they would work to keep their mods up to date so that people stayed subscribed to them, and modders would not have to build an infrastructure to service and support a customer base as if their entire enterprise was a single mod.