How many third party publishers would jump on board a “DMsGuild” but for Paizo IP? I’d think that would work well. especially if 1e was also open on it.
The basic idea, sure. Its the details of the license that would kill it. For one: not being able to sell elsewhere would absolutely kill it. Sales on Paizo's site are so bad, publishers (even those that publish for 2e) are pulling out of the site. It is literally my worst selling location I sell products. I sell more in print distribution and I only have 3 products available via that method. So if I could sell it elsewhere, the question then becomes how do I prove sales and pay for said license. That could be a pain.
The next part is, what do I get for said paid license beyond the ability to work in paizo's setting? For the Traveller license, I've asked for all the basic system books and the overall setting books (High Guard, Vehicle Handbook, Behind the Claw, etc) and I've been given PDF copies. While not much, it is a cost I don't have to incur. Could I expect something like that from Paizo?
Another is their commitment to longevity. Will they shut it down because 1e sales are more than their 2e sales? Whenever they decide to end it (because it will end some day), how much notice will I be given? Will I find out in a press release that it is ending next week while I have a book ready to go or will I know a year in advance? I'd want some kind of commitment to a minimum program length of 3 years at the outset. Also, are we going to find out what they are doing when customers do or can we be given some heads up so we can make compatible products that come out at the same time? I started working on a Solomani Worlds book before the public found out that Mongoose is coming out with a book for that region of space. Is it ready today, no. However, I am much further along than if I had found out about it when the public did.
Next is promotion. DriveThruRPG retweets almost all of my tweets where I tag them. This is especially true for my Traveller products that are on the license. Fantasy Grounds and the Open Gaming Store don't retweet as many, but they do enough. Paizo never does any, at all. I think they liked one of my tweets where I tagged them, like ever. As a result, I don't post tweets to Paizo's store anymore. Hell, I don't even post link to their store anymore. If I'm paying for a license, I'd want their promotional practices to change. Maybe some mentions in their newsletter. I still remember when Paizo sent out a special email to their entire fan base to tell them the Tome of Horrors Complete is available and they really should download it (from their site). Have they done that for any of mine? No. Paizo is very much a "inner circle of friends get the good promotions" company. I'd want hear some kind of commitment to more fairness in their practices on that.
There's more, but you get the overall of what I am talking about. Because of their website and the way their company is structured, creating such a thing would be an uphill effort.