I think one of the things TSR did wrong was that they actually produced material that shouldn't have had a campaign logo and should've been generic.
For example, take Libris Mortis/Open Grave for 3e/4e. Reading these two fine books, I'm struck by how they're just a refinement of the Van Richten Guides and looking back, there's no reason why TSR shouldn't have marketed the Van Richten guides as "generic supplements".
Same goes for a lot of planescape material - Guide to the Astral/Ethereal plane I remember having little Sigil-focused material and thus, putting them under a generic logo might have been better.
For example, take Libris Mortis/Open Grave for 3e/4e. Reading these two fine books, I'm struck by how they're just a refinement of the Van Richten Guides and looking back, there's no reason why TSR shouldn't have marketed the Van Richten guides as "generic supplements".
Same goes for a lot of planescape material - Guide to the Astral/Ethereal plane I remember having little Sigil-focused material and thus, putting them under a generic logo might have been better.