I think a more interesting question is, outside of Tiger Woods...
Which player would have still won a major in the modern era without a caddie? Carrying the bag for 72 holes, up and down often very hill golf courses, getting all your own yardages, raking your bunkers, keeping grips dry in the rain, having one to bounce ideas and confirm judgments with, having an ally, helping you with a read on the green, etc...the list goes on and on
So while a caddy doesn't win PGA Tournaments, the chances of winning on Tour without one is basically nil, (unless no one has one..)
P.S. I suppose coaches in other sports like Basketball, Baseball, Football, etc that actively advise during a game are also equally worthless?