Playing Devil's Advocate, or in this case Devil's Layman. As much as I hate the bad taste it leaves in my mouth to bring this argument:
The initial licensee (one working directly off the SRD) creates a derivative work from the Open Game Content within the SRD. This can be anything from writing a character class based upon the concepts and rules within the SRD to taking the entire SRD and converting it to HTML, Markdown, or other formats.
The resulting work is a derivative work created by the licensee, using the permissions granted by the license to do so, but the copyright for the derivative work only covers the additions or changes to the original work, not the original itself. (derivative work
It would therefore appear to follow that the licensee only has the right to offer a license to their additions or changes (or rather, to offer their OGC
to be combined in the license with other contributors offers.)
This appears to be backed up slightly by
Stating that you need the rights in the first place to contribute material as OGC, an indication that Your Contributions are considered at least here, separate to the OGC within the work as a whole.
Now, taking into account
read in conjunction with
At no point does the license mention the right for the licensee to sublicense any of the Used OGC. Instead, it seems to pass on the license offer from "the Contributors". Not making on their behalf, simply passing on the message that the Contributors have made offers - so if one or more are rescinding that offer, it's no longer available to accept.
This leaves the downstream licensee only able to "pass down" the OGC for which a valid offer still remains - that which any remaining Contributors own copyright to - their specific enhancements made in their derivative works - plus of course their own. Or in other words, the offer is made with big holes in it where OGC has been withdrawn.
I'm hoping here that as someone with zero actual legal knowledge, that I've missed something important and am horribly wrong.