One Western movie actor made a name for himself in Hollywood by excelling in the beloved genre — so much so that he won an impressive three Oscar statuettes. Despite the performer's success, the Academy of Motion Picture Arts and Sciences (AMPAS) used the actor's landmark achievements to change the voting rules for its Academy Awards. Meant to honor artistic and technical merit in the film industry, the annual Academy Awards have changed quite a bit since their inception in 1929. Since the Oscars are the oldest worldwide entertainment awards ceremony, the substantial changes it has weathered aren't entirely surprising.
https://screenrant.com/walter-brennan-three-oscars-wins-rules-changed/