Matt and I have spent the last few years making our way through all six seasons of the half-hour version of "I Love Lucy" -- each episode, in chronological order. The other night, while watching a season-five episode, I realized something very interesting: the quality of "Lucy" started to fade in the fourth season and did not improve in the fifth. Season four is my favorite -- that's where the gang goes to Hollywood and Ricky makes a movie; but I noticed that the show overall stopped being as funny and could never figure out why.
Matt and I have been huge fans of the current television show "The Big Bang Theory" since it started. We are watching the new season (season five; note the similarity). It remains the funniest show on broadcast television ("South Park," on cable, is funnier). We still love it, but it also started being less funny in its fourth season -- just like "Lucy."
Why is this? In season four of both shows, the scripts began focusing less on the ensemble and more on the person who got the most laughs: Lucy on "Lucy" and Sheldon on "Theory."
"Theory" was originally funny because it focused on normal-Penny's interactions with four "fish out of water." That interaction was VERY funny indeed and had to be why the show was so popular -- we all feel we are fish out of water at some point in our lives and, therefore, we can all identify with their situation. "Lucy" started out with essentially the same formula: Fred and Ethel are the normal ones and the fish out of water were Lucy (ditsy) and Ricky (a foreigner in a foreign land).*
Over time, both shows began focusing less on the ensemble and more on the person who got the laughs. This change in direction skews the stories away from the humor to be found as the ensemble interacts, and more toward one person getting obvious laughs. Slowly but surely, "Lucy" episodes began focusing strictly on Lucy getting into some absurd situation (the entire European-tour-driven season five). "Theory" has not slipped all the way down that slope, but it is well on its way. There have been episodes where Penny has had a couple lines and that's it. ("Theory" has made the additional error of adding many more regulars. This not only diverts focus from the core source of humor, it also dilutes the humor that comes from that core.)
There is no arguing that "Lucy" is the best comedy show to come out of early television, just as there is no denying "Theory" is still funny; but it is interesting to note similarities in shows more than 50 years apart, and how Hollywood continues to make the same mistake.
Post script: Jack Benny was arguably the funniest man on radio and the early days of television. He did two things right: he hired the very best writers he could find and made sure the jokes were spread around to all his cast. As obvious as the latter might seem, many of the early radio stars hogged all the jokes for themselves (most notably Red Skelton). Benny knew the important thing was that the JOKE got a laugh, not which PERSON got the laugh. By spreading around the humor, each of his cast members were able to shine in different episodes. This was the key to his longevity on radio (1932 - 1955) and on television (1950 - 1965); and why he remains popular to this day.
*You can get an idea of how much "Lucy" changed by listening to episodes of "My Favorite Husband" -- the radio show that spawned "Lucy." Here, ensemble interaction drives the humor. This interaction survived the early seasons of "Lucy" (many episodes using the same scripts as the radio show) but then slowly changed.