Intelectual work like writing, researching, teaching, etc. despite being important, don't have intrinsic appeal such that people naturally and voluntarily put money on it. We are not built like that.
This is where institutions like universities, governments, etc. come in.
Every piece of professional work has an intended audience, and that means selling to that audience.
A work with no intended audience is a hobby.
But, yes, good salesmen for things like enterprise software can do quite well though you more exposed of the vagaries of the market than someone more removed from the front lines.
Science was doing pretty well before it became institutionalized in the early 20th century. It's not without tradeoffs, but these aren't essential components.