In an interview with the Archive of American Television, Gelbart, who passed away in 2009, groused over the need for an artificial laugh track:
“The laugh track was always a thorn in our side. The laugh track, as we know, is a holdover from radio days, when live people came into a studio and laughed out loud at live performances they saw the actors giving, with microphones in front of them. Well, television, was in the beginning run by broadcasting people and they brought that tradition over.”
You might recall watching sitcom reruns where, at the outset of each episode, one of the cast members informs the viewer that, for example, “‘Happy Days’ is filmed in front of a live studio audience.” This was all well and good for a three-camera show, which was shot and staged to run like a piece of live theater, but “M*A*S*H” was a single-camera sitcom. They were working on a soundstage without an audience. So once each episode was completed, Gelbart and the series’ producers/directors would have to go into a mixing studio and advise the editors as to the intensity of the laughter. As he told the Archive of American Television:
“All of these laugh tracks are primarily, these days, of dead people. These are people who left a long time ago, and are still laughing, only they don’t know it. I always thought it cheapened the show. I always thought it was out of character with the show.”
Ultimately, CBS agreed.
Source From: www.slashfilm.com