Will League of Legends die one day?

People have been saying that this will happen since 2012 and here it is still the most famous game

Honestly, not a lot of "similar" game has died. You're not comparing it to the other MOBAs that failed, you're comparing it to the "Most popular games" before and after it. AoE, WoW, Runescape, Starcraft, DotA, Maplestory, etc all still have regularly active players. With tons of people looking for nostalgia nowadays, these once "Top" games still maintain dedicated playerbases that are not as big as they used to be, but are pretty loyal.

It's already dead consider how popular it was in the past. But it's very popular for a dead game. i mean, even when it's dead, it's so popular.

Yes that's for sure, if it doesn't evolve or try to do anything new then it's inevitable

League will definitely die as all games do but it won't be anytime for the next decade imo