There are many jobs where the range of productivity is higher than 30%. Entertainment and athletics are obvious ones, but whether you think programmers of a given title/scope could be 10x different from each other, it seems like most people would agree that there's at least a 1.5x spread. Same would seem to be true in sales, modeling, acting, music, athletics, writing, film-making, and other fields involving significant creativity or where performance varies greatly.