It's also possible there were all kinds of copyright and licensing hurdles, or that nobody just had the balls to approach TSR for the rights. Back in the day, some complete amateurs got a licensing deals just because they thought to ask, as TSR was expanding aggressively and wasn't looking too hard at who was asking.

As contrasting example from WotC and Hasbro era, 4th edition would've made for decent videogames but they never got done because somebody was sleeping on a license. Videogames based on earlier editions had done fairly well and even launched franchises of their own, so 4th edition videogame at the right time could've done wonders to the edition.