Hi Oystersauce,
There is a big difference between making enough money doing what you love just to get by, and generating massive income to become wealthy. You will be playing a different game.
The answer to your question is "Leverage". You must leverage.
There is only three ways to leverage to generate massive income:
1) Time
2) People
3) Money
Yes, you can start a school, then you can have other teachers teaching for you, but you would have to manage it like a business if that is what you want to get into. Or you can leverage your time, where you can teach multiple students in one go.
As an Entrepeneur, I'll give you another advise. You want to find money elsewhere so you don't have to worry about making money in doing the things you love, and in order to do that you need to learn how to make "Passive Income". Money coming to you while you are sleeping!
There are only less than 5 different ways to obtain passive income, that will be another topic.
Good Luck

Regards,
Ichky