The strategy is also weird in the sense that if I wanted to play a MMORPG, I could play one right now. World of Warcraft has certainly seen better times, but it's not like there is any risk they would turn off the servers tomorrow.
So I have a theory on this.
MMOs seem to be kind of cyclical/generational, and people tend to be wary of them if they're presented to them as MMOs. As an example I'd present Destiny, particularly Destiny 2. It's "obviously" (ahem) a particularly grindy MMORPG vaguely disguised as an FPS (I say this having played it). But the vast majority of people playing it are 10-15+ years younger than me, and virtually all of them missed out on WoW and the whole MMORPG thing. So they think this is this totally novel experience, and that this is just a cool "online FPS", and are only, as they get older and bitterer, starting to realize, maybe this is actually just a grindy MMO (I know a few voices in the wilderness always said that lol). If you read articles or watch videos by Destiny 2 players it's almost hilarious how close a lot of what they say is to WoW players, especially talking about how great certain things were/are, the ways they defend it and so on.
So I don't think WotC want people to think of OneDnD as an MMORPG. One thing they seem to have understood is that, when 4E (which had a nearly identical strategy but 10% of the budget and only 20% of the evil, if that) suffered hard because of the MMO comparisons the then-CEO (I believe it was) of WotC made, where he talked specifically about the ambitions to make it "like WoW". I don't think he meant quite literally, but in terms of a digital online subscription thing? Absolutely.
And games like WoW can't be monetized to the same degree without people throwing a fit.
In WoW, you're paying a hefty subscription. People have shown they'll tolerate mounts/pets being sold, as long as you throw huge numbers of both at them every expansion, and obtainable purely through normal gameplay. People will pay for new expansions, but they won't pay for old ones (so WoW folds everything but the newest expansion into the sub). FFXIV is similar - people are slightly more tolerant to paying for stuff, but it also has a lower subscription.
Because OneDnD/3D VTT "isn't an MMO", it can be monetized much more aggressively without triggering the same red flags, at least for a few years. Subscription, sourcebooks, adventures, virtual minis, dungeon tiles/dressing, virtual dice, and more!
And that's the key. Nothing lasts forever, but WoW made $2.7bn one year, and if they could even break $500m with 3D VTT, that'd prove it was at least semi-worthwhile investment. If they could go higher, or do multiple years of that? Good god.