What exact business principle are you referencing when you mention"running sustainable profits instead of trading long-term viability for short-term gain."? To be clear long-term gains are the goal, no one is disputed that as this is common sense but repeat business is the goal of a business and how businesses grow. MTG for example makes money of selling the core set but it is repeated business in terms of booster packs that keeps the profits coming. What Mearls is saying lines up with a business decision to not focus on the book portion of D&D so much as the other portion by a company who needs a certain amount of profit for something to be considered worth their while. Splatbooks actually do make money. That is how most RPG company's stay alive in the current era not the 1990's but they don't make the kind of profits for a major corporation like Hasbro to consider an investment in. Thus we have microtransactions on D&D Beyond, we have board games, stuff Hasbro understands very well.
Here you are speculating because again WOTC has not said how much money they have made from book sales alone compared to other editions they have just released total profits. People have actually asked this question and never gotten an answer. If I was a gambler I would solidly bet that D&D Beyond alone accounts for a good portion of these profits via the microtransactions available there. Microtransactions are highly profitable as "free" video games like Marvels Contest of Champions has shown.
Well, 1. I said I believe it was Ryan Dancey not sure it was him. 2. The person was just telling what was a general principle of how RPG companies view things. Basically they (he didn't say WOTC) he was referencing RPG companies in general believe that not coming out with a new edition every 5-6 years is leaving money on the table. How he ran or didn't run the company is irrelevant to the conversation. 3. Assuming what you say about him is true that does not mean he does not know what he talking about. That is like saying just because a professional football player failed to get a touchdown they don't understand football. It is a a common type of fallacy because it is an attack on the person not the person's argument.
When I said ahead of D&D I meant ahead in terms of editions produced not sales. I try not to state the obvious because I feel people should get the obvious. Bottom line, I will agree splatbooks don't produce the profits Hasbro wants. As far as it killing product etc pretty much every RPG company in existence proves you wrong. Let's not forget that up until a few years ago Paizo with Pathfinder was beating out D&D. I am not a fan of Pathfinder but it was successful and I guess still is. By your admission Paizo should not be successful because they churn out books all the time and we are not talking about the 1990's. They made a huge shift in the RPG market without Hasbro money behind them and again I am not a fan of Paizo or actually more specifically I am not a fan of PF (I have nothing against the company). It is my believe is the only thing holding them back right now is the complex rules set of PF 2 vs the streamlined but still customizable ruleset of D&D 5E, and by by convoluted I mean the core game not the splat books but the game itself is dense which is not appealing to many people. I think if paizo just produced worlds and adventures and optional rules for the 5E system they would be golden right now instead of focusing on PF2 but I guess they have audience that wants what they offer and market diversity is good.