You can beat T13 with an item level 110 weapon (the relic is not needed). "Most" people who have been grinding relic weapons right now are finishing their novus / working on nexus, while the hardcore are fully caught up. A large chunk of people spent a good 30-100 hours on atma, a good 75+ hours on animus, a good 75+ on novus, etc. The appeal of these weapons are that not everybody will have them due to the fact that a lot of work is required to earn them. That's the entire appeal. This isn't overcoming a challenge (which you can justify a nerf)...it's overcoming a grind. You don't need relics to beat T13 or any of the difficult content. You make relics easier to earn - and you kill all incentive to keep current with them.

Everyone might as well just work on their relics whenever the stages get nerfed. Why should animus and novus get nerfed when there are still countless people working on them and investing the full amount of time? A game is allowed to have missables. How many people have a Dalamud Horn from defeating Nael Van Darnus? Probably not a lot. I don't see the community in an uproar. Falling wayyyy behind on a relic is technically not a missable per se.