Why do some champions get nerfed on the spot while others take months or never get nerfed?
When AP Soraka became popular, she got nerfed after 2 patches. When Lissandra got popular, she got nerfed after 2 months. When Vlad got popular 3months ago, he was about to get nerfed next patch but they canceled it because he isn't picked as much in competitive. So why didn't you wait 3 months for the other two and not nerf them if they lost popularity like Vlad?
When Azir became popular (so on release 10months ago), he's still strong and they are just addressing him right now on PBE. When Sivir became popular since the season started, she got a cute little R nerf that did absolutely nothing. I can tell because in every game in competitive she's either banned or picked. Every.Single.Game. When Rumble became popular two years ago and started challenging overbuffed champions that all got nerfed: Maokai, Hecarim and Gnar, he still didn't get a single nerf.
I'd like to know why the window of action is so different for every champion. This isn't fair because some tend to lose popularity and avoid nerfs like Vlad and Diana, and others are completely avoiding the nerf hammer like Sivir and Rumble.