Because you can do more "staging" with a taped or filmed program than you can with a live performance. You can work in more spectacle, and folks today want spectacle just as they did at the time that Aristotle wrote the "Poetics" or Shakespeare wrote to the groundlings. Because you can get tighter shots and more dramatic effect in filming or taping and subsequent editing than you can when the whole stage is always in view.

This is not a defense, just an explanation.