I appreciate both this and the realities of development in general, but ranking (or the lack thereof) at least appears to be "in flux and in dev" a hell of a lot later than literally any other feature. Meanwhile, other features, some of which were at least initially unpalatable to the "1%" were revealed far earlier, with far more confidence, and far less concern about "flux". In that context, it's hard not to feel -- if you are a member of that diehard constituency who play Halo games come rain or shine for year upon year until the next one is released -- that your fanboy purchase is being taken for granted, and other constituents actively courted ahead of you.
Also, while I will not dispute that it is a small minority of players who are vociferous about having visible ranks, I think the people who you say don't care may not consciously care, may not report caring, but still actually do benefit from ranking, and are moved by ranking, in ways they don't really consider.
Also, the Pareto principle is at work here. The sizeable majority may not "care" about ranks, but the minority that does -- and cares about 'competitiveness' in general -- also tend to be some of your most devoted customers, the kinds who go and make threads on other forums, drive conversations and communities, buy map packs, hype your games, and play them day after day after day, long after the majority has got distracted by newer, shinier things. Attending to that minority -- or at least being more obvious in respecting what they cherish -- has implied value for the franchise far down the line.
The problem isn't that they get to see the sausage being made; it's that the butcher is serving them last, if at all.
Edit: I also appreciate that they are the hardest audience to please, and will happily call you 'cunts' when you fail to, so I can understand why you might throw your hands up and dismiss them. But to do so is probably bad for Halo in the long-term.
