Might be a casualty of the general decline in motorcycling. Bike sales have been declining for a while. Millennials appear to prefer the relative safety of video games.
I don't agree that US CSS prices are high. In fact, I'm surprised they can provide such top notch instruction on top notch equipment at the price they do. I didn't realize how totally spoiled I was by the CSS experience until I just did a RideSmart track day at COTA on my own RR. While it was a third of the CSS price, I had less than half the track time, and that was continually interrupted by red flags and so I was on cold tires most of the time. I was using my own bike, tires, brakes, gear, trailer, etc. I got approximately zero instruction and even had to pay for a crappy lunch. The experience is worlds apart.