I am struggling to understand how they are earning so much.

They mention getting between $1 to $40 per thousand ad views. Let's say on average $10.

A video that gets 165000 views is only earning $1,650--not bad for a days work, but not millionaire potential.

Unless I am reading it wrong and '165m' means 165 million but that just doesn't seem possible that one in five English speakers on Earth would watch one video.

Either way, I am very happy for his success. It's clear he found a particular niche to fulfill.