Being an actor is a lot harder than some people realize. There's a lot on the line every time you get up for an audition. If a casting agency or director doesn't cast you, its YOU they passed up, not simply your product or idea. Its a very personal kind of rejection. The actor opens his/her emotions completely and is at the complete mercy of those in charge. It takes a lot of trust in oneself and in one's abilities.
And how can I fit everything that is "me" into 90 seconds of a monologue? or in 32 bars of a song? or even 30 seconds of dance or standup? Do they realize the kind of perfection that one has to have in order to accurately portray all of their abilities in so little time?