Literally thousands of researchers, professors, entrepreneurs and engineers.
You know of those four (and can't think of anyone else!) because Elon Musk sold his vision to investors, employees, and the public through impressive salesmanship and an obscene amount of both grit and persistence. He aggregated resources and did what you do when you accumulate wealth for business purposes; he spent it to forward his goals. Some of which went towards impressive PR stunts and people wrangling.
You know of those four (and can't think of anyone else!) because Elon Musk sold his vision to investors, employees, and the public through impressive salesmanship and an obscene amount of both grit and persistence. He aggregated resources and did what you do when you accumulate wealth for business purposes; he spent it to forward his goals. Some of which went towards impressive PR stunts and people wrangling.