Have to get that ad revenue

They were originally 10 minutes or less than when people found out if they compress the video file they can make the video longer.
I had my account on YouTube since 2007 but I was on it for over a year before that.

Could you imagine if that's how they did Let's Play videos?

Youtube used to restrict videos to less than 10 minutes. Plus, this was back in the days of videos as a hobby. Nowadays, you get people uploading video essays (which I love). Really the length is more because people have things to say, not based on ad revenue. You don't get much from ads. The per view is low and on top of that, people use ad block. Using Patreon is an better way to make a living through youtube.