The surfing has won over the boaters simply due to ease of operation. The boats can handle the rough public waters, the surfing is low impact, and easier for people to get started on. The whole family and friends can fit in the boat and enjoy a party even those who don't surf It's a "good time" for everybody and you can do it all day long. Skiers on the other hand we need calm water, 3 maybe 4 people in the boat if you squish. We are spent after 2 sets. If you are not a skier you likely have zero interest in participating.
Myself I have always enjoyed the "lake life". the early mornings, the calm, the swimming, the cruising around the lake, the cold bevy in the hot sun, the other lake dwellers doing the same. The skiing is the part i like the most but without the rest of it, it wouldn't be the same for me. It's all a part of the package that makes this sport awesome. But because our boats are small our circle of friends we get to share the experiences with doesn't really grow unless we provide an environment that includes people watching from shore or more importantly enjoying themselves while they wait for their turn or watch from shore. There needs to be something for them on shore. Ski clubs are a great way to keep everybody involved.
Here in BC Canada private water is very difficult to find and finding a body of water that will permit waterskiing outside of the major public water ways is again very difficult. Result is very few ski clubs. Having recently participated in my first couple of tournaments I was able to see what a ski club adds to the enjoyment. The kids were coming off the water smiling, their parents and siblings and friends were cheering them on from shore. The people that weren't skiing had music going, playing games, making new friends, BBQing, swimming etc.... I may have enjoyed it more than most because I am a skier but the environment looked fun enough to my 10 year old daughter to get her interested in learning to ski. (previously she had shown little interest). So the issue is not that the sport is not fun or that the culture is not a good one. The issue is with access. Ski clubs with a focus on the "whole package" are super important to the sport if we want gain interest. Having said that those clubs need access to water. We don't need the water to be water ski club only. Why not share it with a rowing club, or a diving club, or a kids summer camp etc.... here where I live its the way we are regulated that limits our water access. Private lakes don't really exist here, the idea of legally digging one likely never gets passed the idea part. The lakes that would be ideal for the sport will be very difficult to convince fisheries to make an exception to allow skiing. And so we settle for early morning sets on public water hoping we get to at least do that for the foreseeable future. Growing the sport kinda takes the back seat when you're just hanging on to what is left hoping to maintain before somebody decides "courses on public water are no longer allowed" or "This lake is paddle only now".