If it has not already been planned (but not announced), HBO should consider taping Fish for HBO broadcast
They already have/had a relationship with David. Many people who are fans cannot get to see it before it closes or simply cannot get tickets. Many simply cannot afford them even if they were available
The talk about Jason Alexander replacing him after he leaves would automatically remove it from must see status. It would be a rerun of It's Only A Play after Lane left.
They recorded Billy Crystal a few times so this should be considered by the suits @ HBO. It can be withheld from broadcast after the show closes as I doubt it will have life after Broadway. It would all depend on the costs & if HBO felt it was feasible.
Count me in as someone who thinks HBO filming Fish in the Dark is a brilliant idea.
Curb Your Enthusiasm fans have been clamoring for the return of the series and were somewhat placated by Larry's TV movie Clear History. While that was available for all Larry David fans + HBO subscribers to see immediately, and for anyone to view when the DVD came out, Fish is running for a short time, sold out incredibly quickly, and was not nearly as affordable as an HBO subscription. It just makes good sense that HBO would make this available, considering their very close relationship with LD.
Also, I'm a big fan of posterity, and I think it would be (partially) a shame that a portion of Larry's catalogue won't be able to be seen after June 7 -- that's also part of the appeal of theater, though, that only a certain number of people can say they saw him on stage. And that wouldn't really change if they taped it and released it next summer.