It's only this way to keep old content relevant because they know players would happily move on if given the ability to. It worked in XI because the content you ran for a relic/mythic/empyrean still dropped relevant gear and items, but in XIV..you're LOOOOOOOONG past needing anything the content drops except for the tomes.
But that's just not true. We saw in the 2.x relic line that content could be kept alive without the reason for it being tomestones. The reason for keeping old content in the mix is so that new players can get it done.
Yeah, the 2.x era was still "new" so things didn't get outpaced like they do in 3.x. You had 2 sets of relevant tomestones, relevant crafted gear and item drops, relevant gear drops from dungeons, quests that rewarded you relevant items for completing weekly (i.e Primal Focus) and even the primal gear largely had a use for quite some time, namely Leviathan and Shiva, so things didn't seem as bad. In 3.x, you only 1 relevant and 1 semi-useful set of tomestones but unlike 2.x, a lot of the gear isn't really that useful to you since they tend to be lower ilvl than something else you can obtain easily, which is why people always say the new dungeons are 'glamour sets', so a lot of of the 3.x requirements is heavily based around tomestones to keep older content flowing because WT doesn't take you into quite a bit of 3.x era content, it's heavily weighed on 2.x content (especially if you notice you can predict your objective rotation despite supposedly being "random") though that might change in 3.5.
That's why moving back towards making relevant crafted items is a good start, but for the relic quest, they're laying into the tomestone requirement heavily because that will keep people running the older content especially this late in the game. Wonderous Tails ended up helping out too, but I don't know about your server, aside balmung, PFs for WT stuff dies out within the first 3 hours after reset though. 3.x content was being obsoleted much, much quicker than 2.x content did which was something they actually planned. So I'm more referring to the 3.x relic questline.
We had lights, we had animus books, we had dungeon atmas... all these things kept old content alive and full of people without being strictly about the tomestones (I do realize animus books cost tomestones, but that wasn't the entirety of that step).
Yep. 2.x had a better design though still fairly grindy. Though in the long run it's all because of the all too common "delay" that happened at 3.0 that we ended up getting what we did because they later had to balance the questline with that of gaining a top tier raid weapon. If they had time to actually do the quest as planned it probably would have been the more "quest oriented" system they stated it would be. I don't care about grinds, but when you really look at how the relic quest progressed, you can see when things changed (not so much for the better.) Early 3.x relic quests were ok, but..that changed PRETTY quickly lol.