Much like JKR, all they had to do was keep their goonish opinions to themselves and...well, not rake in the money like she does, but presumably do okay with their museum endeavor. Heck, they probably could've continued to get away with selling their TSR-branded t-shirts and dollar store dice.
For a second I though you were talking about the Cranberries here and was wondering what I missed! (You weren't, right?)