I have the same rule with social networks. I'll sign up right at the beginning, but I won't participate until I see a good chunk of my friends are on it. I don't want to invest the time if it is going to flop.
Great example, Studio 60 on the Sunset Strip, a 2005 comedy show written by Aaron Sorkin. It's ratings weren't great and it was canned, but I think it's amazing, and I rewatch that one season at least once a year.
Either way, while I agree with you on not liking the ending (and would have loved it to become as popular and long-running as The West Wing), still extremely glad that it became one of my "re-watch whenever I have nothing else to watch" shows, and still love it each and every time I see it.
Thats why I dont watch series that promise a distant final revelation after 4234 seasons like Lost.
TV shows, at least in the way they are currently produced, are only valuable if at least some subset of the masses likes them.
Just like social networks. they are only valuable if at least some subset of the masses likes them enough.
And you can't relive that new social network experience on DVD.