Rebuttal from a struggling playwright (
me):
Theater is not boring. Bad theater is boring. Good theater does bring a level of intimacy to the performance that cannot be translated on a screen or t.v. It brings one in closest contact with the storytellers without (hopefully) spoiling the story. There is little or no distance in theater--not the kind of distance found in film or television. You are right there as it happens. Each performance is slightly different; each has its own idiosyncracies.
Theater need not be expensive. I often go to the theater in Philadelphia, and unless I'm seeing a large-budget production, I can go for less than $15. Sure, it's more expensive than a movie (not by much), but what extra I pay is worth it for the experience. I have no interest in the ridiculous Andrew Lloyd Webber spectacles, or Broadway revivals. I can easily go see competent, exciting productions in smaller theaters in my own city, and get much more out of them.
Is there a lot of bad theater? Yes. Are there a lot of bad movies? YES. Is there worse television? Do I even have to answer that? People's attention spans are shorter; they crave car chases and bad sex (i.e. there is little that is erotic, but much which is pornographic). Theater tends to shy away from this, and try to tell a story (good theater does, anyway).
Theater isn't boring; it's the audiences that got boring, which you even allude to, pastcat.