Scribe
Legend
Pathfinder happened.
WOTC assumed during 4e, that the community would migrate through editions. But many didn't and the OGL let them move to another game. So bad that they had to go back to the OGL with 5e.
They don't want that to happen with the VTT and other future financial projects.
WOTC should just be honest that it is their fear
That sure would be nice.