WotC is part of a potential open gaming movement, for reasons outlined in my original post. If for some reason one could reasonably describe an open movement as specifically excluding any publisher, or any subset of publishers, then the movement has failed.
The GSL is a system license designed to allow publishers to profit by producing D&D compatible products. Its benefits and drawbacks are irrelevant to open source development. It occupies the same space as the d20 license. The d20 license was also irrelevant to open source development.
The OGL, in theory, was designed to allow for open source style development, as Ryan talked about in the links above. That didn't happen, though plenty of good designs did use the SRD as their basis.
Regardless of 4e's relationship (or lack thereof) to the OGL, an open source approach to design can help gaming as a whole for reasons I outlined above, such as by promoting a culture of design, discussion, and invention.
My contention is that the economic and social benefits of open gaming development - making money by publishing a game, the prestige of pointing to a published book with your material in it - are at best short term benefits to specific subsets of the community.
Cultivating a culture of design via open source methods has the potential for great payoffs by creating an environment of study and learning. The actual games produced by or tinkered with by such a group are irrelevant compared to the *process* of tinkering, creating, and learning.