>>44958815There wasn't a need for it like there was in gen 2 so they didn't put it in the game, simple as that.
I can't blame them for not having it, it was integral to the creative vision they had of gen 2 taking a more open, almost sand box like structure that was meant to be beaten in increments over time, hence it was given things like a daily and weekly cycle and timed events, along with having very little story, in order to encourage this type of gameplay.
Gen 3 is more structured, linear and also more story oriented game, so they likely figured all those elements of the gen 2 games clashed with the pacing and feel of the games, where in gen 2 it went hand in hand with it, and so they cut it out.
Having a night and day cycle be visually apparent wouldn't have hurt the games, and in hind sight I would've liked it, but the reasoning for why it was left out are clear, it would've served literally 0 purpose. Pokemon fans expect every game to carry over essentially every feature because in their eyes concepts like pacing, tone, game feel, and the creators vision don't exist, such things are too complicated, they'd simply prefer each new game be the last game with new areas and pokemon.