The cold hard numbers suggest that Minecraft is well past its peak. MS sold 50M copies for 2 years, which is ~ 70K/day. 2016 they have sold 50K/day. Also:

https://www.google.com/trends/explore#q=minecraft

And really, 100M is already "absolutely massive" in my book. How much bigger can it grow? Will everyone on Earth be playng Minecraft?