I think it was.
If 3.5e is D&D to you then WOTC going 4e and stopping development of 3.5e was taking your D&D away. OGL was specifically designed so we didn't lose D&D.
Yeah like, I don't want to go full Face-Heel or Heel-Face turn here, but I gotta agree with
@FrogReaver.
For some people, apparently quite a significant number, 4E was the death of D&D.
It wasn't for me. I like it! But like for other people, that was it, that's not D&D anymore!
And when Pathfinder got announced and so on, as someone who at the time wanted 4E to succeed, and supported WotC's vision of D&D, I never thought "Those dirty scoundrels abusing the OGL!". In fact I thought the opposite! "Oh good, well if they don't like 4E, those philistines, they can go play their own version of D&D, and no-one even needs to get mad, because they can coexist, thanks to the OGL!". Indeed that was a relatively common viewpoint that people often used to attempt to defuse edition warring threads.
Imagine incredibly the edition wars 4E would have caused without the OGL!!!!!
Can we just imagine that for a minute. It would Edition World War 3. No-one would have survived. Cockroaches would be the only things left posting on ENworld. Again I love 4E, but it was controversial as hell (in large part because WotC are idiots). The OGL saved D&D. There I said it. If 4E had come out, and there was no way to make an alternative 3E-like D&D without creating a new system and possibly even going to court, that would have all been so much worse, so much higher stakes!