So I was thinking, Steve Jackson Games has Warehouse 23 which not only hosts their own products but other RPGs and wargames as well. They also have a lot of IT experience having been at the forefront of using the Internet since the 1990s.
Perhaps a W23 version of the Dungeon Masters Guild is a path for SJ Games to allow the fans of GURPS to publish their own material but still have some type of control and get return for the use of their IP. Along with their other games that have dedicated followings like Car Wars and Ogre.
GURPS Fans who despise the idea of third party GURPS supplement would be covered as there is a single area that they can avoid.
And perhaps this program can be extended to the other games they host if those publishers are interested.
Realistically I don't see happening right away as everybody will want to see what happens with Wizard's experiment first. But the Dungeon Master's Guild work it may be a good compromise between the publisher wanting to keep a tighter grip on their IP than what the OGL allows and the fans wanting to keep some control over their own original work.