The "laugh track" as we know it was invented during the early days of television as a bridge between shows which were *truly* enacted before live audiences in studios and those which were filmed like crocodile teeth - one episode, then another, then another, in the same week - with no audience present to laugh (or sigh, or shit or fart).
In my opinion, it's been obsolete since The Dick Van Dyke Show and I Love Lucy.
Problem is, we've been so conditioned to being cued to laugh (or sigh or shit or fart) that we're uncomfortable without the laugh track.
Or so Hollywood and big producer money tells us...
(er, what the fuck am I doing there?!)