PbtA has its own problems...and much like D&D it seems to be a narrow system that works for a specific style of play, with a lot of designers jumping on its bandwagon for "name-brand" recognition without actually bothering to consider how the system actually works or what kinds of experience it promotes at the table.
I guess I kind of mis-spoke when I said that D&D dominates theory discussions, because in most conversations I've had about the gaming experience it tends to be the case that D&D is used as a regular example of what not to do in a good game, with comments about how people run decent games despite the D&D engine rather than because of it. Yet still, it's the most heavily marketed game, the 800-lb gorilla in the room, and other games get so little exposure in the grand scheme of things that when people get disenchanted by D&D the majority just walk away from the TTRPG hobby altogether, with a minority hacking the system (often treading the same paths that a hundred hacks have done before), and an even smaller minority designing their own games (which are often vague knock-offs of the only game they know).
It seems that very few people actually want to talk about why certain games are dysfunctional. However, I do agree with the original post's assertion that when people do start talking about ideaas like this, their different experiences at the table often lead them to misunderstanding one another arguments...or just devolving into insults.