Interesting observation
I asked a friend who never saw the short before but I new he was a fan of all films from all decades. He watched it thought it was funny. I asked him what made the short work, he wasn't sure so he watched it several times ( 4 or 5). He came back to me and told me the reason "Beginner's Luck" works is due to one reason and that was the character of Spanky's mother.
I asked further to clarify what he meant but he didn't give me an answer. So i'm asking is it she seems to be a single mom or at least single in the short? Is it she is a stage mom and pushy? Is it that everyone is against her and she doesn't know it? Is it that this whole thing was her idea and it falls apart? Is it that she insists that he be taken off the stage and then says she will rescue her son? Is it that she is an attractive woman? Or because she looses her dress on stage? or the stage prop ? Or her freezing om stage? I'm not sure but i'd sure like to hear opinions.