I think there are a few factors in play.
First, 5e 2014 benefitted from three external boosts: Stranger Things, Critical Role, and Covid. Covid is done and CR is moving on, and this is the last season of Stranger Things.
Second, many traditional markets dominated are becoming more fractured. A lot of folks still read the WSJ or NYT, but their dominance is lessened. Products like Shadowdark and Cosmere and Daggerheart are eating into 5e 2024 appeal.
Third, a lot of unforced errors by WOTC. OGL and Pinkerton scandals. Lackluster products. “Under-monetization”. VTT and AI statements. Layoffs that turner off long time consumers. VTT failure. Loss of recognized “stars” in Perkins and Crawford. Larian moving on from D&D.
All combined I think 2024 will limp along rather than enjoy the heights that 2014 achieved.
Very much this. In 2014, eyes were starting to turn towards D&D, it was showing up increasingly in many areas over the years (Sarah Connor Chronicles, Futurama, Stranger Things, The Gamers, etc.), movie stars were even talking about it and streaming live plays. Covid really turned things upside down - suddenly a lot of people had free time on their hands and it appears a lot turned to social games - board games, RPGs - to fill two needs at once, with something to do and a way to interact with others.
Basically, in 2024-25, the world is a much different place than then. A lot of the world has moved on and the iron was cooling by the time WotC struck with the new books. WotC's taken the plunge and they'll have to swim forward with the changes they made, there's no going back (well, they
could do a New Coke reversal, but I don't think that's happening; too much pride, investment and lack of backlash).
To me, in the end it's not much of a big deal. Things change, the world moves on, old product adapts or dies and companies stand or fall, often over resistance to change, some outwardly silly choices in hindsight or plain dumb luck (or lack thereof). There's still plenty of 3PP producers to slake any 5E desires I have, and a 50 years of back catalog if I have a hankering for the Old Ways - which I'll admit I've had at least a desire for some B/X or 2E in the last few years. It's amazing D&D as a hobby has survived so long, but in truth at this point I could care less whether WotC carries the banner forward on or not. And a good portion of the time of late, I'd just rather they didn't.