A couple other thoughts on that list I posted of the top-running Broadway shows. The highest show by Rodgers and Hammerstein is Oklahoma!, which is in 22nd place with 2212 performances. Not far behind is South Pacific with 1925. Once upon a time, Oklahoma! held the record for the most performances of a single Broadway production, and you have to guess that the total seemed pretty damned impressive back then. What would anyone have said then if you'd predicted that someday, a show with people in cat costumes would run more than three times as long?
It is also perhaps worth underscoring the fact that once Phantom tops Les Misérables, Andrew Lloyd Webber will be the composer of the two longest-running Broadway shows in recorded history…and he will likely retain that distinction for a long time. An awful lot of folks in the theatrical community already hate the man and his work…and once that is noticed, they'll probably hate him more. Then some day, a critical reassessment will begin and the pendulum will swing the other way.
I also think it's worth noting that three shows in the Top 20 are revivals which did considerably better than the original productions. The original Fosse-directed Chicago, for instance, ran 936 performances while the Fosse-inspired revival has already run three times as long and may quadruple the run of the original. This is interesting to me because in all creative fields, not just theater, there's a tendency to judge the financial wisdom of a project by how it does the first time around. A TV show that gets cancelled after 13 weeks is a flop. A comic book that gets axed its first year or so is a failure…and so on. In the case of comic books, to pick one of these, we have sometimes seen a discontinued title have such an extended life via reprints that it ultimately proves more profitable (and memorable) than other comics which were once held to be more successful.
I don't think one person who saw both the revival of Chicago and the original thought the new version was markedly superior. The prevailing wisdom seems to be that the original was ahead of its time, that it was neglected in favor of competing shows (A Chorus Line, primarily) and that in light of certain developments in the real world, its theme is more relevant today. Whatever the reason, it's obvious that the property had a value greater than its not-unsuccessful 936 performances indicated. One of these days, someone's going to take a short-run flop, probably one of Mr. Sondheim's, and revive it into a hit.