You have to ride a cart. Riding a cart to play golf makes as much sense as a jogger accepting a ride in a car. Cart golf is perfectly fine for the handicapped golfer and is a good invention that was intended for that purpose. Golfers with bad backs who could no longer carry their clubs or pull them in a cart, older golfers that have developed many aches and pains, golfers with bad hearts, etc. But what happened is the perfectly healthy golfer started jumping on the golf-cart and he liked it.
Professional golf is golf with a caddie.
The professional golfer is at the course for 8 hours or more to be at the level he is at. He arrives early and has a diligent warm-up process, he then plays 18 holes walking with a caddie. In other words, the professional-golfer is also in very good condition. At the same time golf started growing, so did the use of the golf cart. Up-scale clubs are requiring you to pay for a cart if you wish to play on their course.