Why don't casting directors have a category for "Best Casting By" at the Academy Awards?
To comprehend this issue, you have to have a deep understanding of how the casting process works.
Casting directors are contracted by production companies and/or studios to cast specific projects. The casting directors (and their associate casting directors and assistants) filter through massive amounts of submissions for specific roles, mainly through talent agents.
The casting directors then audition actors for the specific roles being cast. They then choose what actors that they personally deem "right for the role", at their discretion, and they subsequently advance those actors to a "call back", to audition for the director, writer(s), producers, and for major roles.. the studio executives.
Eventually, the right actor for the role is hired. The actor is not hired directly by the casting director, but rather the director/production company/studio.
Other than for small speaking roles on TV series, the casting director does not have the ability to hire actors, they simply select a certain group of actors to advance in the casting process. I am not talking about extras. Extras are cast directly by Extras Casting Directors/Companies.
For there to be an Academy Award category for principal actor casting directors, the voting members of the Academy of Motion Pictures Arts and Sciences would have to be able to see all of the hundreds (and even thousands) of actor's auditions for each role by the "Best Casting By" nominee, to be able to judge whether or not each casting director nominee did the best job.
And just to narrow down the casting nominees, there would have to be a massive amount of that material available to the Motion Pictures Arts and Sciences nominating committee. That is a logistical impossibility.
Directors, producers, writers, and studio executives have the final say in who is cast in specific roles, not casting directors. The best casting directors do a great job, and they have a great collaboration with those who do hire the actors, however there is no definitive way to establish a criteria for an Academy Award category for "Best Casting By".
I can elaborate much more about the casting process, however that would require much more than I can post here, it would be a complete eBook. I do want to elaborate about why casting directors are never credited in films as a Casting "Director", but rather credited as "Casting By".
The Directors Guild of America does not allow, by contract, any other persons on a film being credited with the word "Director", unless they are actually a "director" i.e. 1st AD (First Assistant Director, etc). That includes the Cinematographer (widely called "DP" or "Director of Photography" on the set).
Casting directors are some of the hardest working people in the entertainment industry, but there you go, that is why there is no Oscar Award category for "Best Casting By".
