Their lead, who actually is a Beyond Skyrim developer, explains here ( Reddit.com ) that they want to join BS eventually, and further down the comment chain it's explained by them and another user what they're waiting for, why they haven't joined yet.
Comment History
Pamasich - - 1 comments @ Cathnoquey; The Fractured Isles
Good karma+3 votes
Profile
Pamasich
joined
This member has provided no bio about themself...