OP is clearly not talking about CT, as nearly every sentence would be lie then.

a) "No one runs the older content." would be a lie, as it pops up daily in my alliance run roulette.
b) "No one runs it more than once so there's no rewards" would be a lie too, especially when Kupo is up, but also for Anima-Weapon, Glamour and other stuff. Also see a)
Alliance Raid is what most people do on a daily basis, as it gives a lot of XP and stones - and most of the time you get CT.

Also it became a very important part of the story, especially in ShB.