I think you've got wishful thinking.
You might be right there. But I do want to make one thing clear. I don't think that this will be the death of D&D or TTRPGs as a popular hobby. I just think that this might not work out as well as WotC is hoping. Moving any customer from a perpetual to subscription license model is hard in general.
I might jump around when quoting your post and reply out of order.
I think WotC is planning on moving a big portion of the gaming community into the digital age.
This is laudable. But I would clarify it - they're planning on moving a big portion of the current D&D player base into the digital age. The gaming community is larger than just D&D.
I believe the first step is to clear away the third party input, which rumor alone has gotten a solid head start. Next will come 6e or whatever they call it, with a strong push into online/remote gaming, and VTT-aided F2F gaming.
I think they need to be careful here. First, "clear[ing] away the third party input" could be seen as WotC using their market position to push out competitors. And that might attract some unwanted attention. Especially if it pushes out VTTs that provide services for other games because they can also serve OGL 1.0 content.
The curse of the current game model, as has been bemoaned here in this site, is that a gaming group often only contains one consistent purchaser: the GM. And pdfs are basically selling on the honor system, what with the file-sharing options.
That's been the state of TTRPGs for a long time, though. Every player doesn't need to buy every splatbook or adventure book. And in many systems, they don't even need to buy the core rulebook. And yes, PDFs are on the honor system. I'm not sure there is a good way to address this outside of some draconian DRM, but then that limits the utility of PDFs.
I'm not sure the solution to this, though, is to try and lock the game behind a subscription service that monetizes all players.
Even if it is, the route that WotC was originally taking with D&D Beyond and the proposed OGL 1.1 wouldn't have solved that problem for 3PP anyway. WotC's proposed terms would have driven them out of the market completely.
As you've noted yourself, a large number of gamers are already conditioned to pay for entertainment streams.
Yes, they do. But adding a new service, or raising prices, causes people to reevaluate if they really need that service or if they should find alternatives.
It comes down to a question of value. Does this service deliver value for the price? Does it deliver value compared to the other services I can subscribe to? And right now, in the moment with everything going on, it's hard to see that value. Especially since the current subscription levels really don't seem to offer a lot of value from a surface glance and they don't really distinguish themselves from the competing options other than being "WotC's platform of choice."
I think the attack on the OGL now really underscores the weakness of their product and market position today. Yes, D&D has a large player base. But if they really had a strong offering, they would have said that they were moving D&D v.Next into Beyond as a Gaming-as-a-Service product under a new, more restrictive license and started to work on exclusives for that service by drawing from Hasbro's extensive library of properties like My Little Pony and Power Rangers.
They wouldn't have even acknowledged any potential competitors or "punched down" at the 3PP ecosystem.