To understand classic Hollywood, it helps to stop thinking only about actors and directors. The studios employed enormous permanent workforces. Costume departments could fabricate a period wardrobe. Construction crews could raise a street, a train station, or a mansion. Music departments, labs, casting offices, legal departments, and publicity teams all operated inside the same industrial system.
Long-term contracts gave studios unusual control over careers, schedules, publicity, and sometimes personal lives. The same structure also created stable teams of technicians whose craft knowledge accumulated from picture to picture.
Each studio cultivated a house personality. Warner Bros. became associated with urban energy and tough social dramas. MGM sold polish, stars, and prestige. Paramount projected sophistication. RKO could pivot from Astaire-Rogers elegance to low-budget experimentation.
The studio system was never monolithic, and it changed constantly. But thinking of the lots as production ecosystems helps explain how Hollywood could release such a vast number of films every year.