Steve Martin

At first it took me aback a little when I first found out that one of my favourite actor/comedians that I loved growing up had apparently given up making movies and doing comedy and had taken up the banjo It didn't seem like it was the same person. I'm talking about Steve Martin, for those who want to know. But after thinking about it, why not? Where is it written that people have to have only one major act in life? Why can't people pursue what they really want to pursue, when they want to pursue it?