There is truth to what you're saying, but it's only half of the problem.
Some of the mentioned content isn't at cap, and, which each expansion, playing old content feels progressively worse. I ran a lot of Delubrum Reginae Savage in EW, and the latest BLM changes made what I used to play (Lost Flare Star Black Mage) horrible. Come 8.0, it wouldn't surprise me if, continuing current trends, Cirterion feels as awful as doing UCoB feels these days.
Until this game stops both disregarding low level gameplay, and accidentally gutting it with its ill-thought "reworks", a lot of this content will never see life even if they build on it beyond a small burst of activity as people trudge their way towards endgame content.
