system
A chat on subreddit /r/NoStupidQuestions
human
The things required to play the game are expensive in and of themselves which is not necessarily accommodating to those of lower classes. 

Yes you could get a pair of golf clubs for a couple hundred dollars but you can get a tennis racket and some balls for even less which is one sport that would be more appealing to more people on a budget. To play basketball all you need is a basketball to find a court somewhere which is nowhere near as expensive as golf would be.

Anyone of any demographic can play golf though should they choose and are diligent enough in finding a way to do so
gpt
Golf is also a past time where rich people can network with each other, which increases the draw for more rich people to start playing.

I know several people who started playing golf just so that they can approach potential clients better