Take your favorite movie that was adapted from a play. Since obviously I don’t know what that your favorite movie adapted from a play is, I’ll pick one and go with Streetcar Named Desire. Watch the classic Kazan/Brando/Leigh/Hunter/Malden movie and it’s great, and it will be great tomorrow and seven weeks from now and 29 months from now or 11 years from now, it will always be great, BUT it will also always be exactly the same.
See five different versions of the live play and it can well be almost like seeing five different plays, all of which might be great in and of themselves. It’s amazing how differently different actors can interpret the same character: you might see one version of Streetcar in which Stanley seems like an almost retarded total thug, another in which he seems like a brilliant sociopath, another in which he’s amazingly vulnerable; Blanche might be so pathetic you cry in one version and hysterically funny but less likeable than Stanley in another and incredibly sensuous in a third, while Mitch (Malden’s character in the movie) might be an obviously sweet but neurotically shy character in one production, very obviously a closeted gay guy in another, and a character who down deep is more despicable than Stanley in another, and that’s with each actor saying the same lines at the same times.
The movie is frozen forever: Brando is always going to rip his shirt and scream “STELLLLLLA!”, but another actor might do that scene very subdued, and another might do it in a way that makes Brando seem subdued, and while some productions and performances are definitely better than others the great thing is that it’s possible for the same play to be produced three times using the same script and one seems like a dark-comedy (because that’s what the actors and the director are hitting), the next seems like a Greek tragedy, and the other one seems like a morality play, and they’re all great and no version is necessarily wrong or right. It’s very fluid, it evolves, it’s alive and malleable, unlike a movie which, no matter how great it is, is never going to change (Karl Malden is ALWAYS going to play Mitch as a nice naive Mama’s boy for example).
The difference in a good movie and a good piece of theatre is the difference between a beautiful painting of a landscape and the actual landscape. Which is better- well, that’s personal choice, but both are beautiful in a “the same:completely different” sort of way.
On the disposable income factor, I feel your pain. I love live theatre. I’d go every week if I could. Unfortunately professional theatre, even repertory companies and “no big names” touring companies of Broadway shows, are getting ridiculously overpriced. Case in point: I wanted to go see Les Miserables in Atlanta next month: the best price for decent (not good, just, acceptable) seats is $115; the $50 seats are in ‘the gods’ (theatre jargon for back of the back and top of the top section). I don’t dispute that it’s worth it or that they have to charge that much, but that’s just way too much for people who aren’t well off.
Your best bet is amateur productions, some of which are godawful and will almost kill your desire to ever see another play and some of which are absolutely amazing and make you wonder why these people aren’t professional working actors. But the great thing is that good or bad, see the same play again and it will be a new experience- it’s a “you never step in the same river twice” thing.