I don't feel like quoting everyone that I want to respond to, so just here's what I have to say.
I think the OP fails to realize the vanity a lot of people have when it comes to this game. And to glamour items in this game. With regards to the cosmetic items, I find a lot of enjoyment out of glamour, and so do a bunch of other players. I would absolutely hate it if I had to keep the appearance of whatever relevant end-game gear was available during a said patch. Especially since some of the gear is extremely unappealing for me. And I think a lot of others would, too. People live for glamour, and I don't just mean in FFXIV. I mean in life. People want glamour, they want luxurious things. Perhaps they're just vain, but vanity is part of human nature. And it seeps into this game and peoples' game personas.
With regards to dyes, they are available in-game, and, on a lot of servers, for a very hefty Market Board price--Pure White and Jet Black dye usually sell for 500,000+ on my server for just one pot. With regards to the Bomb Dance someone mentioned, that was available in-game for one of the Moonfire Faire events.
I don't see how "glamour items, mounts, and dyes" in the Cash Shop made someone jump to SE adding primal fights, trials, and entire storylines to the Cash Shop. What even...? Stop using slippery slope arguments, please. The developers have never given any indication that they would add actual playable content to the Mogstation. None of this makes your argument appealing. If anything, it just discredits it because of the extreme jump from cosmetic items to playable game content.
PS - The ARR Hildibrand trials dropped minions.
Also, people continue to make these threads because they just like to complain, usually. If it isn't about the Mogstation, it's about something else (Cleric Stance, Healer DPS, PvP chat restrictions, Wanderer's Minuet, tanks not dropping tank stance for more deeps...you name it, and someone is probably complaining about it). And so many similar threads pop up because people can't be bothered to just keep complaints to a single thread; they feel the need to make an entirely new thread voicing an opinion that already has 10 other threads associated with it. The fact of the matter is: there are those out there who will simply complain just for the sake of complaining.
Can't satisfy everyone.