The Honeymooners was a simple show, by today’s standards, which revolved around the same narrative, but presented it from a different perspective, with other details than the previous times: a simple recipe for a successful series.
However, back when the show debuted, having a simple plot meant something, since television was at its beginning (as far as sitcoms are concerned). We had one goofy character played by Jackie Gleason who thought the world of himself even if he had no reasons, his wife who had to put up with him, the mostly idiotic friend and his wife.
That was more than enough for a series to achieve cult-status after more than 60 years since it first debuted. The Honeymooners can be considered an archetype as far as sitcoms are concerned.
As said, the plots are very simple and they are served very well by the personalities of the characters. For example, if Ralph found a million bucks at the beginning of an episode, by the end of it he will have lost it. This had no influence whatsoever on what the next episode will be about.
There were no story arcs which span several or more episodes, just like there were no sub-plots. From a modern perspective, this is almost unacceptable – it would be too repetitive and, ultimately, too dull to watch even 39 episodes in which, basically, nothing happens.
However, from a historic point of view, The Honeymooners has a great importance since its blueprint can be guessed in many shows that followed since, especially in The Flintstones and The Simpsons. But, like everything else, these blueprints need to be updated. In other words, sticking to the original concept won’t do any good to a show nowadays.
As a conclusion, there is a reason why The Honeymooners is one of the most revered sitcoms of all time: it set the tone of most of the shows that followed.
Add to this the genius of Jackie Gleason, who refused to do any more Honeymooners episodes just for the sake of the ratings, and you get the Classic 39 (they aren’t called classic just because they were the original episodes).