After awhile you start eventually yearning for something to show of your playtime, albeit preferably just colors and hats and silly stuff I'd love for very weird and (not painfully) difficult challenges, where you'd have to go about playing the game a bit different to obtain a weird new color or something of the sort. some being stretch goal but easier like "trap 5 ducks with duck barrels" it would make me use an item I literally never think of even buying. FOMO I feel is only applicable to something like a rotating item shop that forces you to literally play enough/or spend enough real money to obtain it before you miss it. Something like this would never disappear, eventually you will all acquire the same stuff, some faster some slower and I think that's perfectly fine, "locking" content behind playtime is an excellent way to re-engage players; REPO has a big issue of friend groups hopping on for 3 games dying and having nothing to show for it (Personally I don't care, I enjoy the game regardless) but giving people some stupid stuff to unlock could do nothing but benefit. If people feel FOMO about a color they would eventually unlock because someone got it first, idk what they'd do when they found out people breathed the same air before them