Being a good juggler helps, and I don't mean throwing your balls in the air! I know many pro performers, but very few of these put bread on the table by solely performing. You certainly need some breaks and you can say goodbye to a normal family life. These young ones are trying to do it before they have families, but I doubt if many will keep it up once the patter of tiny feet start. Often seriously talented people musically are also talented in other ways, which helps.