I've got a YouTube channel with over 300 videos and I dunno? 1300 subscribers? Got started by putting up a simple how to on making salad dressing and got some nice encouragement, so I started a weekly food video series that ran for 6 solid years. At one point I had a Patreon account with a whopping 6 people who paid me every week to see the video before anyone else.
There definitely are people who make bank from YouTube. My bet is there are far more people who use it as a way to inform, educate, and bring value to their audience - and then sell a course or membership. Jason Brown (The Brown Report) did a great interview with Jill and Josh Stanton of the Screw the 9-5 podcast awhile ago about how he uses his YouTube channel.
Making good videos is time consuming. YouTube is making it harder to earn money from ads in general.