Prophet of the profane (She/Her)
I'd say, "all these years" only increase the advantage of cultural significance, branding and starting first if we're talking about a product totally dominating the space.Sure but IMO that made a bit better argument before 4e and 5e as the cause for D&D’s popularity. But it doesn’t explain 5e’s popularity relative to 4e’s. What does is the difference in the game itself. There’s something more to it than starting first and branding, especially after all these years.
With each passing decade, chances that something will ever replace Coca-Cola are getting more and more slim. Or Google. Or YouTube.
For me, Coca-Cola is just a part of life that existed since forever, not really different from water or even the sun in the sky. I've been drinking it for my whole life, I've constantly seen it in movies and heard it mentioned in songs. В руке банка колы, в кармане пакетик с киви-и. For me, Pepsi isn't a soft drink, it's a Coca-Cola-like.
For modern internet users, especially young ones, Google is such a thing. Bing, Yahoo or DuckDuckGo aren't search engines, they are Google-likes, to the point where "bing it" product placement in some movie I don't remember felt almost like a joke.
D&D existed since forever, and is a most prominent roleplaying game, that is often referenced in TV, film and videogames. Other games are D&D-likes, and, probably, will forever be.
All in all, I can't see D&D being really eclipsed by anything now, in 2E 21, even if WotC will wake up tomorrow and decide that the dice must only be played on certified birch dicefields. I can see that happening in the eighties, though.