If there is market value in a skill or knowledge, the market will find the people who can be trained in it, then train them. Perhaps a talent is required to be competitive.
Corollary: Beware of fields which have artificial gatekeeping. They are in a disadvantageous market.
Become the best in the world at what you do. Keep redefining what you do until this is true.
Borrowed from Scott Adams: It's hard to become a top 5% in a given field. It's easy to get to the top 20%. So find two synergistic fields where you can get to top 20%. This makes you a top 5% cross-disciplinary expert.
There are no get rich quick schemes. That's just someone else getting rich off you.
Often, it's other people getting rich off of the efforts of a huge mob, while making a small sliver of that mob fantastically rich.