Paying for a license would be nearly impossible, as the OBS team would need every contributor to sign a CLA to give the OBS team the rights to relicense/dual-license the OBS code base.
As long as they all pay a reasonable license fee, I don’t see a disaster. The OBS project could then pay developers to build open source features that benefit all. A lot of the forks would likely contain features that are not if interest to other users anyways.