Yes but most of the time that's new stuff released it's not like they go back and remove old raid mechanics from ARR/HW because people want to solo them or go in via unsync'd. Ever hear the term can't appease 100% of the players/people 100% of the time.
You would argue for it because you want it, but that doesn't mean it's worth the effort to do so when you can arguably just make a new character. Just because you're lazy and don't want to rerun the full content doesn't mean that they should just make quests repeatable. The proverb teaching a man to fish doesn't apply to this.Regarding this change, I'd argue it would be a very "easy" and efficient way to give people something to do in the game for the simple reason that once they set up a system that allows to re-do quests they dont need to develop any new content specially for that system and yet give people who enjoy doing quests an aweful lot of content to do. Give a man a fish or teach him how to fish and so on.
If you want something bad enough then there's no excuse, you just do it. For example there's a few NIN glamours I want from 2 different dungeons, one of em a 40 and the other a 60 exp both have been ran about 15 times each in order to get the glamour, but I've not gotten them yet, does that mean i'm going to give up? Nope, just makes me more determined. If you farmed a relic when they were current or even when they're not you know the suffering people had to go through to get it, they wanted it bad enough they put forth the effort.Right now I'm not logged into the game because theres nothing to do - if I could replay the Hilli-quests for example, I'd defintely do that though!
By giving people the option to re-play quests they'd basically "create" an aweful lot of content without having to develop that content (a second time).
Saying "Not everyone wants that" isnt a great argument not to put something into a game thats filled with things to pick and choose from.