J. Randy Taraborrelli said this quote

Today...major actors and actresses develop their own projects or, at the very least, cherry-pick their roles carefully to suit not only their tastes but also whatever image they have cultivated to present to their public. Most major stars have their own production companies through which such projects are developed and even financed. While the biggest male stars of that time did in fact have their own production companies--Jimmy Stewart, Kirk Douglas, John Wayne, and Burt Lancaster, to name a few--and thus exerted creative and financial control over their careers, that was not the case with female stars. But Marilyn Monroe was about to change that.