Talespire, a beautiful tabletop simulator on steam, has stated in their FAQ that they are open to working with other companies. Now that DnD beyond is working on their own tabletop simulator It would be great to see Pathfinder nexus as well as other demiplane toolsets have some sort of integration with Talespire. If that is something you guys at demiplane are interested in please reach out to the Talespire dev team! I for one would love to see it!
Not to speak on their behalf, but I would assume this sort of decision would have to be made by publishers (Paizo in the case of Pathfinder) or at least require an additional agreement with them. D&D Beyond is now owned by D&D’s publisher WotC, who have long sought to make their own VTT. It’s unlikely that Demiplane should be the relevant intermediary for the publishers, unless it’s for an in-house VTT rather than an external collaboration.
That being said, having some sort of integration that would allow one to sync characters, rolls, homebrew, etc. (like Beyond20 for Foundry and Roll20 or MrPrimate’s D&D Beyond Importer for Foundry) would be nice.
Also, FYI, Pathfinder has official modules for both Foundry and Roll20 (and possibly other VTTs).