Yes, because it served its purpose at the time, which was to get many more people playing and continuing with Dungeons & Dragons 3rd edition (and its 3PP off-shoots) than it would have if there had been no OGL. I personally believe WotC did much better financially over the 8 years of 3Es run than it would have otherwise without the OGL.
I also personally believe WotC made more money switching to a non-OGL 4E than they would have had they just released a 3.75ish 4E... because despite everyone's claims that Pathfinder specifically was really what most players wanted, I firmly believe had WotC released it rather than Paizo... it wouldn't have been received nearly the same. After the 3.5 revamp that bothered many players and seen as a money-grab... had they released a .3.75ish 4E they would have been slaughtered for it by many in the playerbase as a definite money-grab and nothing more.
It's only because it was Paizo specifically releasing their version of a 3.75 that made many players stick around and accept it. One, because many of them really liked what the company did with the magazines and were more than willing to stick with them after what they felt was WotC giving Paizo a raw deal by taking the magazines back. Couple that with a 4E game they didn't feel was an improvement over 3.5, and it made players much more ameniable to moving on to a '3.75'. Pathfinder was from a company they preferred, it worked specifically with a series of adventures they enjoyed, and it meant they didn't have to play a new version of D&D that they didn't like.
All things that I don't personally believe would have been in WotC's favor had they done 3.75 themselves.