Yes: the ads you see on YouTube are split between the creator and YouTube. Now that I'm a larger channel there is patronage and sponsorships as well, but it all got started with building an archive of popular videos.
I don't remember the number of videos, but my goal was 200,000 subscribers before leaving my day job. Subscribers aren't views (and they mean less now than they did when I started) but that was my estimate on how big of a base I needed to be confident it would work. 200,000 subscribers wasn't paying me as much as I earned as a full-time teacher but I knew the lines would cross.
Just curious, how many videos do you upload? From what I am seeing, maybe 5 minute video 1 per month? How long do you spend on this in total (research, sponsors, video editing, etc...)?
Again, this is amazing to me that people can make a living off of youtube.