That's basically a sample size of n=5 from which you inferred that "has macros" and "is popular" are causally linked, which should get you expelled from every statistics department in the world ;)
My guess is that various syntaxes for doing basically the same thing fade in and out of popularity randomly and for the most part independent of their feature set, just as different ways of covering the body with cloth fade in and out of popularity. Last year's collection isn't unpopular because it became to hard to use, people want new stuff and they don't want to be associated with old stuff.
No, no, I don't claim that having macros is required for popularity. I claim only that the growth pattern of "simple" markup languages is to add features which make them no longer simple. At that point, new simpler markup languages appear, and the cycle repeats.
My guess is that various syntaxes for doing basically the same thing fade in and out of popularity randomly and for the most part independent of their feature set, just as different ways of covering the body with cloth fade in and out of popularity. Last year's collection isn't unpopular because it became to hard to use, people want new stuff and they don't want to be associated with old stuff.