I know, that there was such thread and it was closed. But I have new evidence. Why RNG in combination with time-gating actually cause FOMO? Because players hate to return to obsoleted content to chase that one thing, they're unlucky with. I have exactly such problem now. There are 3 trinkets per spec in ZM. 2 of them are BIS. And 2 of 3 are guaranteed drops from sand piles. 246 trinket is guaranteed drop. But one of 242 ones - is RNG drop. Problem is - which one of them drops. BIS or not? I was unlucky on 2 characters and didn't get BIS trinket on them. And now I have to chase this stupid trinket, while all other gear is already BIS, so I would want to switch to other characters. How can I get this trinket? There is drop from rare. But WowHead says, that chance is 2%. Lol, yeah. It's guaranteed drop from WQ. But in both cases it's base item level is 236, so it also has to proc to 242. I'm not sure with what chance. I guess, it's very low.
So, now I've got stuck with this stupid trinket. I have to camp this stupid rare on two character every day. Even if chance is 0.0000001%, it's still extra chance. And I have to do all trinket WQs. I also think about doing it on all my characters at the same time to avoid such situation in a future. And it's just bad. It's unhealthy.
Players want to avoid such terrible situations. They want to do everything in time, when they still do other content. So, they tend to start doing it early. I.e. instead of doing such things on one character after another, they start to do it on all characters at once. It's hard. It's unhealthy. But players feel, that they miss something, when they skip opportunities to get such time-gated RNG rewards. They have fear of missing time-gated CDs. And by definition - it's FOMO.
And you know. Game shouldn't encourage unhealthy behavior. We fight against smoking, drinking alcohol and drugs for reason. Because people have different levels of self-control. And it's natural. It's just wrong to say "Problem doesn't exist - just use your self-control". So, I think, that FOMO-encouraging mechanics should be removed from game. It doesn't mean, that time-gating and RNG are bad. Time-gating should exist to protect players from overwhelming themselves. And RNG should exist to make every character unique. But they shouldn't be combined to provide time-RNG-gated rewards, that cause lots of FOMO.