This goes deeper than you may think. Apparently Calobi used to be one of if not THE top YouTuber for an app called Pixel Gun 3D. It seems 2017 is when he transformed his channel into what it is today.

Surprisingly there are still many remnants from this period. He still has a profile on the Pixel Gun 3D forums (which actually gives us his birth date) and even his current Twitter banner is still from this period

I'm not trying to shame Calobi or anything for this, I used to be really into Minecraft and Minecraft inspired games around this same time. I just found it interesting how vastly his channel has changed. I also find it interesting he's still using his old channel.