Person A works at a hamburger place and flips burgers for living.
Person B works as a brain surgeon at a hospital.
Who earns more?
Why does one person earn more?
It's because one has a more complex skill than the other one.
Person B spent thousands of hours of learning a new skill, how to operate a brain of a human being.
Person A spent maybe 1 hour to operate all the machines in the kitchen (you get the idea).
You get paid in proportion to your skill level.
One very profitable skill level that will ALWAYS be in demand "How to more customers for your clients". That is a complex topic, but can be quite lucrative.