It might be a big win, but I would question whether or not the possibility of CR switching to Daggerheart would actually impact WotC enough to warrant them ever having been truly concerned? I mean from my personal POV (as uninformed as I will freely admit)... it feels like CR switching Daggerheart would be much more of a risk to CR themselves and a possible drubbing of their business model than anything WotC might suffer from if CR did.
Would CR using Daggerheart potentially reduce WotC's overall success with D&D 5E24? Sure. Would it cripple them? I don't believe so. Not even close. However, I think CR would be much more likely to be crippled as a streaming business if their switch to Daggerheart didn't pan out. I mean I know they now have a large fanbase that cares more about them as a group than about any particular game (since their streams that use other systems still generate an audience)... but can their business survive if their primary stream numbers dropped to the same level that their shows like Age of Umbra do? I dunno. But it seem to me the odds of CR getting truly hurt by a bad switch are much higher than WotC. And if WotC believed that too, then perhaps they took the calculated risk that CR wouldn't cut off their own nose and thus WotC didn't feel as though they had to pay into the CR with some sort of sponsorship deal. They might have assumed CR would make the same determination that we all have done, in that it is the combination of both the cast AND Dungeons & Dragons that have allowed Critical Role to succeed as well as they have. So why change things now? Tryin to sell some more Daggerheart books is not nearly a good enough reason.
Especially when they can, and do, have Daggerheart streams. It would be highly risky to try to push viewers into an entirely different system especially with a new GM and rotating groups of people.