The big open question in my mind is, "How much of D&D's recent explosive growth has been COVID-related, and how long will the pandemic persist?" I'm sure it's been an important part of the growth story, but I'm even more sure Critical Role, MDCM, and others have been a lot more important.
This game started getting really popular on my college's campus back around 2017 or 2018 to where I started wondering what was going on. I'd use D&D examples in my classroom to ham up my nerdiness to the students and keep them engaged, and from around 2017 they weren't laughing at me anymore (I wanted them to--that was the point): they were now laughing along and then talking about campaigns they were in. By 2020 it seemed like half the campus was rolling d20s at least once a week.
"Is it plateauing?" I don't know. "Will its growth stay as explosive as it has been?" I mean, how could it? Things like this always have to at least slow down at some point. So long as the market doesn't contract, though, I imagine WotC will be just fine. Never underestimate a nerd's willingness to keep putting more cool stuff into their shopping cart.