Kyogre absurdity

So it was unknown to me that the only time I was able to get Kyogre was when I fought him in the deep cavern. Now this means I can’t get Rayquaza and I can’t get UFI. Why is it kyogre you can’t find again after you beat it but hearten and volcanion go to their respective places after you beat them?

You’re supposed to capture one of Heatran and Volcanion in that battle. Since you can’t get them both in the same battle, at least one has to respawn. Since that is already in place, they will both respawn if you kill both.

I know but I just think its sort of dumb that kyogre doesn’t reappear after you rematch the elite 4 like every other game

Kyogre isn’t the main legendary of the game.

what does that have to do with it? and he actually is one of the main considering you know the abyssal cult

The Abyssal cult is minor relative to Mew and Giratina. Ho-oh and Lugia don’t respawn in ORAS because it isn’t their game.