I agree with what you said but sometimes all you have to do is to find a good market, a good product/service to offer your value to someone who is willing to pay a high amount for service/product rendered.
For e.g. Sales workshop or Knitting classes. You can command any amount for such knowledge based classes. And there is scalability. Regardless if it’s 1 or 20 students, you’ll still be teaching the same thing. Hence, it makes sense to get involved with such business model