Berkshire Hathaway conferences, yes, there's a money/class thing there. Golf? Somewhat, especially at upscale courses, but there are a good many moderate-income golfers. (The only serious golfer I know is a semi-retired truck driver.)
Skiing is quite egalitarian, at least for those of us who live in the mountains, and especially if you include cross-country, snowboarding, snowshoeing, &c. Equestrian events depend on the sort of event. If you're seriously into e.g. show jumping, yes, that can take serious money and run into snobbery territory real fast. If you just like to ride, or do things like cross-country/endurance racing & mounted archery... Well, the two people I frequently ride with work as a payroll administrator and an EMT. Other occasional companions are everything from nurses to schoolteachers.
It seems, though, that the real predictor on many of those things is not income, but age. How many young people play golf, or bowl? (Though I think bowling must be a regional thing, too: where I grew up back east, I knew of quite a few adults who bowled. Here in the west I don't think I've ever met anyone who does.)