“Hail Caesar!” is a gentle comedy on the surface, but seems to me more a homage to the glory days of the Hollywood studio system in the 1930s-50s. At that time the “big five” studios (Warner, RKO, Fox, Loew and Paramount) controlled every aspect of film production, from script writing through to distribution. Actors were on contract to a studio, who managed every aspect of their career and their public image.