Casual fans won't notice it ... yet. The ripple effect, they will not be able to avoid.
Let's say MCDM (Matt Colville's studio) stops producing D&D content. Not a single word mentioned of the game again on his YouTube channel. That's 418,000 subscribers who will notice.
Let's say Matt Mercer doesn't want to sign the agreement to basically give WotC permission to publish his works without giving him royalties. That's 1.86 MILLION subscribers.
If Wizards goes through with this, D&D is going to lose market prominence. And I'm not being hyperbolic. After the struggles with MtG, if they slaughter their only remaining cash cow, there are going to be heads rolling.