Will CSGO ever die?

No, it wont die. The Counter-Strike series has not and never will die. It's just a classic game. The popularity has fluctuated around 500k and thats pretty good. I think it might be because there are a lot of other games on the market that gets a lot more attention than CSGO and might give an illusion that CSGO is dying because it doesnt have the attention that the other games have.