Being a street artist is not easy. Unlike any other type of entertainment, almost all of the members of your audience, did not plan on watching your show.
They were planning on doing something else until you convinced them, either with your actions or your words, to stop and watch. This by itself is difficult. On top of that, the audience gets to see the entire show before paying a dime. There is nothing preventing them from simply turning around and walking away at the end of the show.
What other form of entertainment lets you watch the entire performance, and then lets you decide how much it was worth to you?