They’re different. It’s like saying “why would anyone watch a game of baseball when they could watch football?” or “why would anyone go jogging when they could be riding a bicycle?” There are superficial similarities, but fundamental differences. You may like football while I prefer baseball, and you may like biking while I prefer jogging, but because they are superficially similar doesn’t mean one must be superior.
Part of the appeal, especially with community theatre, IS the personal connection – I don’t live among Tom Hanks or George Clooney or Meryl Streep or Jodi Foster. I live among the people who participate in community theatre, I may run into them in the grocery store or at a restaurant, and some I may even be friends with. To see people I live and work with, people who are a part of my community or people I’m even friends with transform into a different character on the stage gives a different perspective from watching a relative stranger assume the role.
Aside from that, seeing something on the stage is simply a different experience than seeing it on the screen, with different benefits and different downsides.
There’s the saying that more people are more afraid of public speaking than of death. Go and see Leatherheads at the movie theater and George Clooney doesn’t know (and doesn’t care) that you – or anyone else, for that matter – is there watching it. Go to a play, and the actor can see you, and, in fact, the entire audience. Clooney isn’t going to feed off the audience’s response to his performance.
Also (having done it in community theatre a couple times), I have a huge respect for the actors’ contribution to the show. For that hour and a half or two hours, you must be focused on the show, your lines, your blocking, the other actors and completely in “show mode”. There’s no second chance for that performance – even in a professional show with eight or more shows a week, every night’s show is “out there”, and if you’re not on, you don’t get to take it back and it’s not going to wind up on the editing room floor.
And that applies to everyone involved. All the actors and all the crew have to come together and execute a perfectly orchestrated performance, and get it right the first time. And it’s not even so much that it’s great when it’s perfect – I’m appreciative of watching the attempt. With movies, when it doesn’t work, it’s “CUT! Take 2!”
Why do you suppose an audience claps at the end of most any stage show, while rarely doing it at the theater?