People are doing a lot of axiomatic reasoning on this thread: "FOSS works this way, so the WOTC license should work similarly". Nope! Your best bet is probably just to go read actual legal analyses (that's all I'm doing, reading and relaying things).
1. IP licenses, especially one sided take it or leave it licenses, are revocable, sometimes even if the license expressly says otherwise because of restrictions on perpetuities.
2. A license turns into a contract when there is consideration from the other side. Licensing your own work under a license because of a virality/share-alike clause has mixed reactions on if its consideration but more fall on the side that it is than it isn't.
Neither of these positions would seem to be to distinguish the OGL from GPLv2 here, and position 2 would set a position where OGL is not revocable but MIT/BSD are.
Further, there's also quite a well established argument that the GPL v2 would withstand an attempt to revoke the license: https://copyleft.org/guide/comprehensive-gpl-guidech8.html#x...
The text that that argument relies on in the GPL v2 is simply not present in the OGL v1.0a.
Apache prior to 2.0, all versions of MIT or BSD also do not go out of their way to be irrevocable.