That's what Udemy's really about. Not too long ago, I crossed the 200,000 student mark:

It takes persistence, wise topic choices, and a fair amount of luck to have that sort of impact - but just think for a moment about the opportunity Udemy presents for anyone to affect that many lives. Every week, I hear from students who found a better job or a new career, and my courses were a part of their journey. I didn't come into Udemy with any sort of existing following or any sort of fancy marketing plan; just valuable knowledge I was willing to share. Udemy connected that knowledge with people around the world who needed it.
See this football stadium?

It would take 3 of them to hold all of the students who bought my courses on Udemy.
That's why you're here, folks. Udemy is an opportunity to share your knowledge in a scalable manner with an enormous audience. You can change lives for the better, without even leaving your home - and make a decent living in the process, even while providing that knowledge at prices that are accessible to almost anyone.
It's true that most instructors won't have this sort of reach, but isn't helping out even one person worth it? Isn't the opportunity to impact a much larger audience worth it? All you have to lose is the time it makes to produce a course.
When it works, students win, instructors win, and Udemy wins. We're all in it together.