Complexity Of Balancing The Game.
Players are consistently inconsistent on how they want the state of the game to be and the meta. It would not be hard to balance the game in such a way that games lasted 25-40 minutes again. But the game devs are always stuck in a struggle between allowing players to solo carry games because they earned a lead through lane/jg dominance or letting players who chose to be more passive/scale for late game teamfights and objectives. Should you be awarded a free win because your team has a 4 item Kog maw and Lulu or should the mid lane Talon be able to pub stomp the game in 20 minutes because a Orianna didn't pay respect to his level 2 Power Spike.
Season 8 was a rocky season. Yes Damage was high, but again I've never seen more game diversity since I started playing league. Morde, Hiemer and Skarner all saw pro play this year. Skarner wasn't even playable in solo Q before Predator allowed him to be able playable champion again.
And now with the new changes, Riot is trying to increase lane safety & lane phase, while also trying to keep the abily to solo carry in tact.