As more and more of the Top PGA Touring pros focus only on playing in the Four Majors of Golf, the few opportunities the golfing public and fans will get to see these very popular players will be few. As a result attendance at many of the PGA Tour events has dropped so far that even the financially healthy sponsors are finding it hard to justify the expense of being a sponsor of the event.
When sponsors leave, so does the event from that community which cuts off any exposure to the game of golf to the many people who live in that effected city.
Naturally, the less exposure people have to the game the less popular the game will be to play. The trickle down goes all the way to the local driving range not having enough business to stay open.