Quote:
13. Termination: This License will terminate automatically if You fail to comply with all terms herein and fail to cure such breach within 30 days of becoming aware of the breach. All sublicenses shall survive the termination of this License.
This is probably the strongest argument as to why they can't deauthorize OGL 1.0a, since they mention it is perpetual, and they do not have an end date listed, you have to look at what termination clauses exist.
Like, they had a section on how the license can be terminated, and they don't have "make a new version" as one of them.  WOTC will argue they are not terminating, only de-authorizing.  But that has the same functional effect.
Still, awesome move that is going to cost a ton of people a ton of money and a bunch of lawyers to get settled.