From the perspective of say Paizo, from what WoTC says now, Paizo's existing material can stay up, but they won't be allowed to publish anything new. That goes the same for say Basic Fantasy, or any other 3PP who uses the 3e SRD. If they do press ahead, this will still need to be fought in court.
It looks like with this announcement WoTC are hoping to pick off some weaker animals from the herd. But fundamentally:
1. They spent 22 years assuring everyone OGL 1.0 was irrevocable.
2. They now say they are revoking OGL 1.0.
So the strategic situation has not changed.