You are trying to argue that a party can enter into a private law agreement, at time zero, with another entity that doesn't even exist at that time. But you can't point to any legal principle that explains how that would work.
You are trying to argue that licenses can be created over IP that doesn't exist yet. You haven't explained how you think that works, by reference to any legal principles.
But doesn't section 4 do exactly that? If not as a pool, at least individually? Doesn't each Contributor implicitly agree to, at future point in time, to an as of yet unknown new User, to grant them a license?
I don't know what you mean by "a pool, at least individually".
Putting that to one side, section 4 does not create any agreements between non-existent parties, nor any licences over non-existent IP.
Under section 4, the offeror/grantor (X) confers a suite of permissions (summed up in the definitions of Use, Distribute and Derivative Material) in relation to the OGC whose use constitutes the accepting party's (Y's) entering into the contract. Note that both X and Y actually exist - a non-existent party can't engage in the conduct set out in section 3 that constitutes acceptance of an offer.
Under section 4, the accepting party (Y) agrees to use the OGL, which means that Y comes under duties in relation to other parties' Product Identity and also come under a duty to offer to license their copyrighted work in the same was as the offeror has done. This is an obligation falling on Y, in respect of Y's actual work (ie the work that follows from Y's use of the OGC). If other actual parties (Z) take up that offer in the future (by engaging in the conduct spelled out in section 3), then Z will bring into being a contractual relationship with Y.
Y does not agree, at the time of acceptance, to an agreement with Z (who may not even exist at the time of Y's acceptance). Y agrees, at the time of acceptance, to make a standing offer to all the world. No legal relationship with Z comes into being until Z accepts that offer, which requires (among other things) that Z exist.
And a more general point: in my experience (which in relation to this topic dates back to 2008), most posters on these boards - and I include you and @FrogReaver
in this category - do not have a firm grasp of, or at least do not clearly articulate, the difference between a present offer, which remains on foot, to enter into a licensing agreement with any party who wishes to take up that offer
and a licensing agreement with all the world
For practical purposes, for most of the OGL's history, that difference has not mattered because no party has suggested that they might cease to keep their present offer on foot. But as has now become clear, once one of the parties changes its mind about that then the difference may turn out to have quite a degree of practical importance.