This seems to be very much the intention, to create a new market, but given who is head of D&D, it will not stop there - his entire CV is about transition people from purchases to subscriptions - so if the 3D VTT takes off there will be strong attempts to persuade essentially all D&D players to use it, I would suggest.
Yes, I expect this is true. For me, personally, I am in favor of this. I wouldn't mind at all just subscribing to the VTT as a service if it does a great job supporting the rules. It would have to be a much better experience than all other VTTs I've used. And I don't mean 3D rendering. That is currently a negative to me. Even if the 3D terrain experience is great, if it doesn't support and automate rules, especially AOE spells, I just have no interest.
I've finally moved beyond all DnD all the time. I expect I'll be rotating systems for my campaigns going forward. I would be happy to pay for a subscription for 6-18 months and cancel it like a streaming-show subscription, so long as while subscribed I had access to the entire rule set, including any updates. If I really find that I love the system and if the books are very attractive and fun to browse, I buy them. But I never use physical books when running my games any more.
I'm probably the target market for WotC, except for my willingness to start and stop my subscription depending on what I'm currently running. This is why I think they will continue to sell (even require you buy) the digital books. It keeps you more invested and a reason to come back to the site/tool, even if you've cancelled or downgraded your subscription.
The other thing that makes DDB sticky to me is that I have a subscription that lets me share my content with my players. This also serves as a kind of "family plan" where I can just share my content with my son without having to repay for him to have the same digital content. Just like I'm less likely to cancel a streaming-show subscription that I'm sharing with family members, I'm more likely to keep my subscription to DDB if family and friends are making use of it, even when I'm not.
We may even see Beyond shut down (or stuff stops being added to it) in an attempt to force people to the 3D VTT- obviously that's a terrible idea - it's also absolutely the approach a lot of companies have taken with various products, and actually it's not been entirely unsuccessful.
Possible but I don't think so. What would make more sense is that they bundle and integrate. When you want to pull up rule text in the VTT it could pull that from DDB or link to DDB, opening a new tab. With adventures, it would be tougher without some coding in the background DDB. More likely you'll need to have to buy the adventure content in the VTT, either paying again, or perhaps there would be some deal where you buy it once but have it in both places. Ideally, there would be tight integration between DDB and the VTT where they are just different interfaces for the same owned or subscribed-to content. There are a lot of ways WotC can do this in a way that makes many of us pay for the convenience without upsetting those of us who have poured a lot of money into DDB.
Beyond find-a-game I believe a mention was made in an interview a while back of being keen to try AI DMs and so on, and I suspect we may well see adventure modules, even campaigns for the 3D VTT designed around the limited functionality of an AI DM or even just choose-your-own-adventure fixed choices instead of really allowing D&D-style play. The idea is to get people on and buying MTXes and subscribing and maybe also buying virtual books, really go through their pockets.
Initially, I say "yuck", but I did enjoy Baldur's Gate. If you can solo play through adventures with an AI DM, it
might be fun. But TTRPGs are all about getting together with my real human friends. For solo play I much prefer a more curated and designed experience that a video game like BGIII provides. I don't even like MMOs. But I can say never. At the pace AI is developing I can see it being something I would enjoy.
I remain optimistic about the future of D&D because I think the 3D VTT will be an absolute car crash that never recoups its costs (if it really has 250 people working on it) and that Beyond will trundle merrily along, being basic and usable.
History tends to support your prognostication, but I hope you are wrong. I would love a well designed VTT specially tailored to support a specific system. This is also part of the reason I'm backing the MCDM RPG and why I'm following Foundry VTTs Crucible project. I'm rather worn out on generic VTTs that try to support any system.