Here's the problem, and it's very well known, it's RNG, I can't stress how that's the problem enough, and not the time investment.

You main argument seems to be comparing it to proper content in the game, here's the main difference:

Every time we failed at Titan EX, it's because we made a mistake.
Every time we failed at Turn 6, it's because we made a mistake.
Every time we failed at Turn 7, it's because we made a mistake.
Every time we failed at Turn 8, it's because we made a mistake.
Every time we fail at Turn 9, it's because we make a mistake.

See the pattern? Every time we fail at every other piece of content in the game, it's because of something we have done wrong, the very opposite can be said for Atma.

Every time I fail to get an Atma, it's because RNG.

You can be doing everything right, Zenith equipped, getting Golds, hitting as many FATEs as you can, and if RNG determines it so, you're NOT going to get your Atma.

Most (not all) the people I've seen defending this quest are people who got lucky those who get all the Atmas in a couple of days. I would definitely like to see how their opinions change if they got unlucky, like myself and many friends, those of us who have spent over 24 hours in one zone to get one atma, and then, almost insultingly, you have those who get lucky, and get all 12 Atmas in that same time frame.

I am more than willing to invest hundreds of hours into obtaining my weapon, but it shouldn't be dependent on RNG, taking some players 12 hours, and other players 12 days.