The big cliff-like hour drop you see at your Riot Games backstage is caused by a huge amount of League players that already stopped playing League for years, coming back to play the loving mode URF, then it calms and cools down to a normal level if you compare the average playing-hour to modes like ARAM.
Look at the actual hour number, try not to look at the shape of it. Urf is actually as hot as, maybe hotter, than TFT.
It's actually a pump-and-dump phenomenon, the decrease in playing time is the overheated passion calming down, it's not people losing interest in League of Legends.
What is warning and alerting might not be this play-hour-decrease lookalike.
Actually what is not normal is the burst of play-time, that is the core of the cause.
That tells you Riot Games that there is a tremendous amount of player base left inactive for so long because they have already lost the interest in playing League.
How can you miss the picture in this dramatic way? You were struggling to realize that a whole lot of people love playing URF, and YOU DISABLED IT, for your so-called "damaging the League" reason, so they just choose to not play the game at all.
Please Riot Games, do not be those guys like the people who made the Youtube Rewind, or the people at Blizzard who made decisions like Diablo Mobile, especially that dude who said: "you guys don't have a phone?".
Try to not be those semi-wealthy kids that had a finance degree working in the financial industry as a so-called analysist that cannot make a profit buying/selling financial instrument because they do not actually know anything.
I personally only play ARAM, I don't play the Summoner Rift, and I know a lot of player base like streamer/cosplayer/professional that only plays ARAM to socialize, does that mean ARAM is hurting League of Legends and should be disabled for eternity?