Alzrius
The EN World kitten
No, it didn't. Again, exactly the opposite happened: various companies and designers that started out making d20-based products were able to develop not only a reserve of capital, but also name-recognition in the RPG hobby market. This allowed them to establish a strong enough position that they could then branch out and start producing non-D&D content later on.Well it enables creativity in D&D kinda of killed off not D&D.
Just look at Monte Cook. Or Green Ronin. Or Kobold Press. Or numerous other "alumni" from the d20 era. Some of them already had credits to their name, to be sure, but they all benefited immensely from being able to use the OGL to their advantage, eventually breaking away from the familiar-yet-profitable to try things that were more experimental.
The OGL allowed for the entire RPG market to flourish because it let newcomers hitch their metaphorical wagon to the big boys (i.e. WotC) long enough to establish themselves, after which they could break away and start making new games that they probably wouldn't have been able to otherwise.