The context of my first statement was clearly that if WotC is releasing it under CC-BY then also releasing it under the OGL is, in fact, 100% moot.
WotC releasing future SRDs under CC-BY and the OGL gains nothing. Once it is in CC-BY, any virtuous virality is entirely voluntary. The only way to maintain the virtuous virality is to release it only via OGL and not CC-BY, which, whether we like it or not, isn't going to happen and with 5.1 released via CC-BY, the ship has already sailed. So, yes, once it is in CC-BY, then releasing also under OGL as well is 100% moot as I said.
I'm not saying this is a good thing, of course! I've been a vocal supporter of the OGL's virality for over 20 years, and I still plan to publish under the OGL (and ORC and CC-BY-SA). And I agree that CC-BY's (at least percieved) greater stability does trade off the important viral heart of the OGL. However, with WotC not bothering to enforce proper OGL compliance pretty much ever and the past decade of OGL compliance being a joke with maybe 1 product in 10 using it properly, the virtuous virality was already voluntary in practice, sadly.
I wish we lived in a timeline where the OGL recieved the support and enforcement that it deserves. But, we don't. The 5.1 SRD is already CC-BY, and the 5.2 one will be as well. As in so many other areas of life, being an Open Gaming giver and not just a taker will have to be largely voluntary (again, in D&D world, at least, the Pathfinder world is a different matter which many overlook).