|Since their inception, the Oscars made it almost impossible for the vast majority of films released in the U.S. to compete for their awards. The rules and regulations were so onerous and expensive to qualify that it made no sense to even consider trying. Big studio films almost always got nominated. Small, worthy, independent films rarely (if ever) received serious consideration.
After the studio system died, the situation began to change, but even today it's hardly a competitive situation.
I'm no expert, but I've been following the Oscars since the mid-50's (as well as the Tonys).