URF: Why we love the limited

Riot not making this game mode permanent speaks volumes of riot's confidence in their ability to create even more compelling game modes. If they made URF permanent, they'd have to rack their brains for something cooler next year, but instead they create a fake scarcity by taking URF away for no reason so they can trot it out next year and not have to try too much.

It's your problem if you have no self control that you actively wear out a mode for yourself, don't make people who actually like the mode wait a whole year for the actual fun variant of this game.

Still a poor reason. More utility > less utility, in my book. If its availability year-round makes it harder for you to appreciate it, then that's personal.