I'm afraid that if they can't make golf as a game of wide popularity and access by the masses, and courses as a part of an overall accepted concept of worthy land/resources use, it will be a rarity available only for the elete. Golf could become an obscure and anacronistic activity by 2050. It may become an anti-social practice due to use of dwindling resources. Golfers may be viewed as a horrid wealthy diletante wasters of resources if they play golf on the remaining enclaves where it is harbored.
Or,
It will become so wildly popular now and into that 2050 era, that people won't put up with any diminshment of the game, will crave more, and the industry will be forced to come up with creative ways of making golf work for society and enviromentally as a benefit. For instance; as happens now, a user of effluent waters. The more people on the planet, and they will demand more recreation. So, golf will have to find a way to accomodate more people on perhaps smaller land tracks using resources in a beneficial or zero impact way, and find a way to push more people through the golf courses more efficiently.