There are alternatives to using freshwater - effluent and desalinization - that are presently keeping golf courses alive in places like Turkey, the middle east, the Canary Islands, Mexico, and so on.
Improved turfgrass varieties like seashore paspalum and ultra-dwarf bermudagrasses are allowing better conditions with less fresh water than even ten years ago. Researchers and breeders are still hard at work and I can't wait to see what they come up with next.
Resort courses especially count on green surfaces to attract customers. That won't change in a generation.
Even if water and pesticides do become more restricted, it won't affect bunkers, which only need an input of sand and labor. Where labor is cheap, bunkers will thrive.
I see kids from 5-25 playing golf every day. Maybe golf isn't booming but, to borrow from Sam Clemens, reports of its death are greatly exaggerated.