I am a content creator in youtube and i do earn money uploading videos on youtube. Advertisers pays youtube for posting their advertisements on videos that content creators like me upload on youtube and youtube pays the content creators from the money paid to them by advertising companies. But there are a lot of other ways to earn money "using" youtube. You just have to look at youtube as a search engine. Actually, youtube is the second largest search engine next to google. With that in mind, you should upload things that people are looking for and are interested in. You could also do affiliate marketing alongside your videos. For example, your video is about how to juice different fruits and vegetables, you could review a certain product and promote it using your video. So when people gets interested in the product and buys the product, you get a commission. Another is by accepting brand deals and the likes. There are a lot of ways to earn through the back end of youtube. You "could" even earn "more" than the money being paid through advertisements in your content.