You’re missing the point. Back then audiences weren’t told when to laugh (that became a thing a bit later). But were more like a live barometer of the script’s quality. The recordings of Jerry doing a standup on a bar stage were filmed the same day. They would test material, improvise jokes, actions and lines on the spot and look at the audience reaction, not because they expected a laugh, but because they were getting a laugh. They weren’t pausing for the editors to insert a laughtrack, they were pausing because the audience was laughing and their lines would be inaudible on the mics. This allowed them to fine tune the show, then during edit make it as hilarious as possible. It was a thing they actually struggled with the sections filmed out of studio, but they showed them to the audience so they got the context for the set comedies. It was a whole art, and the actors were part of the writer’s room. An entirely different vibe from this decade’s sitcoms. Modern sitcoms are emulating what they were getting organically during filming.