So, now, why does it occur to me that if WotC wanted to get out of having to live up to OGL, the best way, maybe the ONLY way to do so would be to publish a new edition of D&D, eg. 4E. Hmmmmmmmmmmm........ Or is this all just a total coincidence? (I generally tend to be of the school of thought that holds that almost every coincidence is no accident!)
Edit: In sum, you only need the OGL if you're borrowing from someone. WotC isn't borrowing from anyone. They -are- the source material (via the SRD). Everyone borrows from them.
IANAL blah blah blah, etc.
Anyways, this is maybe a little bit complicated.
WotC didn't have to "live up to" the OGL, in any sense.
The OGL doesn't give away your (intellectual) property or copyright, it grants other people a right to use it, without asking you*, and provided they follow certain guidelines (primarily, that they use the OGL in turn). You still own your copyrights.
So lets say Happy Games releases the FunLand Campaign Setting, and says everything is OGL. What does that mean? Well, for starters, it means anyone can reproduce the FunLand Campaign Setting, in whole or in part, with or without changes, without asking you, provided they include and utilize the OGL as directed by the OGL**. (One of those requirements, incidently, is that anything labelled OGC stays OGC, so they can't "close" any OGC they take from elsewhere). It also means that -that- version of the FunLand Campaign Setting is always and forever OGC. You can't undo it.
HOWEVER. Happy Games still owns the FunLand Campaign Setting. They are under no obligation to keep it in print or make it available. After the first month, they've made 6 sales, and have decided to pull it back and rewrite it. Six months later, the HappyFunLand Campaign Setting is released. In this version, all descriptive text is closed, and all mechanics are open. The text is exactly the same in both version (FL and HFL), and the FunLand descriptive text is still open, but only 6 people in the world have access to it.
Giddy Games wants to make a GiddyRules version of FunLand. Giddy Games bought 4 of the 6 OGL copies of FunLand, but they don't like the OGL and don't want to use it. So they contact Happy Games and arrange for another license, between Giddy Games and Happy Games, that lets them use the descriptive text from FunLand (they don't need the mechanics, because they're using their own GiddyRules), and a few months later, release FunLand - GiddyRules! The descriptive text in FL-GR, despite being the same as in FL and HFL, is neither open nor closed under the OGL - it's just regular, copyrighted text.
Now, one more permutation. Happy Games added FunPoints to the rules. In the FunLand CS, FunPoints were OGC, even though they weren't based on the SRD at all. Because FunPoints weren't based on the SRD, Happy Games didn't -have- to make them open, and with the release of HappyFunLand, decided to close them. Because Happy Games invented FunPoints, they can decide on a case by case basis whether or not to make them open.
Bringing this around to WotC...because WotC invented D&D, they don't have to use the OGL with D&D if they don't want to (and they don't). The whole of WotC's D&D is WotC's FunPoints. The SRD is FunLand. WotC only has to use the OGL if they use a 3pp's material, and don't want to work out a private license (or buy it outright; see:Eberron).
The problem, from WotC's standpoint, isn't the OGL itself. It's that instead of 6 people downloading FunLand, 6 million people downloaded the SRD. They gave people the tools to make supplements to the D&D system, not (fully?) realizing they were also giving people the tools to replace D&D as a brand.
People made supplements to D&D; they also made competition. And 4e is WotC's way of reclaiming, individualizing, and differentiating D&D from that competition.
*While I understand that asking is the nice thing to do, the OGL was constructed so you don't have to ask. If you were supposed to ask every time you wanted to use OGC, it's licensing.
**While possible, I've never actually seen anything but a "rules" system copied wholesale, and I've never seen that marketed, except for the Pocket Players Handbook and several pdf/online original SRDs. Never a campaign setting or any kind of accessory or adventure.