100% truth here. You can't control external outcomes, you can only control what you do. What you do for a vocation, business, or hobby may not marry up to what the world thinks is valuable enough to make you externally "successful" (whatever your defintion of success is). Essentially that's just luck -- luck that what you are great at or care about matches what the world cares about.

Therefore, you have a choice: 1) bring your passion and love to your work and let go of the external outcomes, or 2) try to chase something that the world cares about.

You can find success with #2. People do it all the time, but there is no way to guarantee you'll have success. Whereas #1 provides you with a lock-down, stone-cold guarantee of success.