This is why I’m not that excited to see more products on DDB. It further centralizes a platform already dominated by the biggest RPG producer in the world. Maybe the practical side of this isn’t a big deal yet, but I do hear more people saying they don’t bother with material unless it’s on D&D Beyond.
I guess my perspective is very different, because (me being on here and owning a lot of D&D books on Beyond myself aside) what I DO is sell physical books. This discussion reminds me SO MUCH of the whole "Print Is Dead" discussion that has permeated my business for 30 years. Longer if you look at it like the "Comics are Dead" discussion that has been going on since the 70's.
The only time I EVER worry about Digital replacing Print is from a top-down position: I worry that publishers will move to a digital-only model in spite of themselves. The reason I say "in spite of themselves" is that it has been widely (and long-ly) proven that there IS a market (and a sizable one) that holds out for Print Products. You KNOW that if there WEREN'T, then they'd have cut out print a long long time ago. The biggest reason why publishers prefer digital is NOT SALES. It's MARGINS. They cut out the printer, the shipping, the distributor, and the stores, and are able to sell directly to the customer.
But I would bet that Print Sales are EVEN STILL higher than digital sales. Even in this day-and-age. Even with Beyond being a nice, centralized place for WotC to sell their product with few-to-no middle-men, it might be responsible for their largest area of profits, but it's probably not responsible for their largest area of sales. And even if it IS (in that they've crossed the 50/50 mark) then I doubt that it is by so large a margin that they can, without shooting themselves in the foot, give up on print sales. They'd simply cut out too much of their audience. My proof is only that I think that if they COULD, then they WOULD.
When it comes to 3PP, I absolutely think that "being on Beyond" is going to give you a huge bump. However, I really think that the bump does not come out of their usual market - in other words, the 3PP GAINS from being included, but it doesn't LOSE anything (or barely anything). Nor do the small 3PP who are NOT included. They are left, just as they were before, a very small fish who has to claw their way to success without any help. Exactly where they were before.
Of course there are people who will only buy it if it's on Beyond! They wouldn't have bought it before either! But there is ALSO a market that will only buy it not-on-Beyond. If that market didn't exist, then a 3PP would never have had a chance in the first place.