I guess it's time

[Azrael]

So it died because too many people are doing it?

It died because the main purpose of aquapolis is to let people make gil.
Since moogle give for free one of the most valuable pieces that drop there (fibers) and people farm that alot, you can see the fiber price dropped from 3m to less than 200k in less than 1 month.
Some other stuff that drop there is needed to make old 170 gear which nobody really uses anymore.
There is so much supply compared to the demand that the items that drop there are almost worthless now.
Only things that are really valuable are the V materias that drop from the last rooms, which is very hard to get to (and you need to try your luck against other people) and even their price dropped alot.
Might just sell the daily map on the market board and be done with it.

[SendohJin]

Since moogle give for free one of the most valuable pieces that drop there (fibers) and people farm that alot, you can see the fiber price dropped from 3m to less than 200k in less than 1 month.

Maybe it was just way overpriced like everything else when people don't know how to get it / don't have multiple paths to get it?

And of course the price will settle down when people hit max Moogle Rank, Moogle quests isn't free, it still takes like 15 minutes to do and you can't get more than 1.5 fibers from it per character per day.

Might just sell the daily map on the market board and be done with it.

What do you think people who buy the maps do with them? Because it's not you it doesn't exist? If it's actually dead people wouldn't buy your maps.