I think demand for legendary armor is high and sustainable enough that the situation may continue pretty much indefinitely. The grind required is huge, and a lot of people are undertaking it with great enthusiasm, and looking at the examples provided by other legendary equipment supports the claim that interest will hang on more or less indefinitely. I'm still constantly running into people who want to do raids to work on that armor or Coalescence, fractals for Ad Infinitum, etc, and those projects have been available for years.
Note that I'm using the word 'may' here because all this is wild speculation about what players will do en masse; it's not a hill I'm going to die on.
You've got some moderately highbrow and transhumanist stuff in there; have you tried Greg Egan? The two starting places I like to recommend are the Clockwork Rocket books (natives of a universe with alternate physics explore it and figure out what's going on, kind of Flatland turned up to 11.. and then up to 121..), and Permutation City which I think will meet your "some very interesting ideas" and then keep accelerating.