I guess it's time

[Velhart]

How do you explain FATEs being dead and lvl50 dungeons being irrelevant then?

I still see FATE parties happen and people do lv.50 dungeons all the time, it is called Lv.50 Roulette. With the relic requiring so much esoterics, that roulette is more relevant than ever, including Main Scenario roulette where you get poetics to buy more crystal sand.

You probably don't see as much FATE groups because SE has offered more options to get from 50 to 60, when the options at the launch of the expansion were pretty limited to spamming dungeons or FATE's.

As long as the deep dungeon is a decent way to earn EXP, then it will always be relevant.