I actually think the answer is even simpler than this, and not so much about the cost of the horses but due to two other factors:
- Group lessons are really rare in dressage barns
- Dressage barns in the west tend to be trainers taking stalls in other people’s facilities, and stalls are expensive.
By contrast, western and hunter barns with lesson horses are often really longstanding old facilities, with a riding school, and with group turnout for the lesson horses. They may be even on the second generation, or have an owner who bought the place 30+ years ago, when land was cheaper. Dressage is a relative newcomer to the west, so there aren’t many trainers who have been teaching dressage here for 30+ years.
One of the ways you make money with a lesson string is to have a barn full of kids, possibly including summer camps. We haven’t found the mix that creates kids that want to take dressage lessons and dressage trainers who want to teach kids. In any case, a riding school is hard pressed to make money without at least 4 people in the ring on average; I grew up in lessons of 8.
(One reason dressage doesn’t do group lessons is that dressage arenas aren’t really big enough for more than two, three riders tops to really work in effectively, and usually a trainer is assigned one ring.)
Dressage lesson horses are usually retired horses from previous clients, and have been pampered all their lives, so they pretty much are used to being in stalls. Horses used for beginner lessons in jumping and western are often of types that are more amenable to being chucked out in a field as easy keepers. There’s no reason you couldn’t seek out such horses for a dressage lesson program if you wanted, but these days building a lesson program with school horses from scratch is pretty much prohibitive in any discipline. You don’t see young programs in western or hunters either IME.
I think this is a real chicken and egg problem for dressage, because it’s absolutely true we don’t have schoolmasters to teach our up and coming riders, and less and less do we have any programs at all for beginner riders to learn the basics of riding any horse.
I think there is potentially demand, even, for a training center that would allow adults to go ride high end schoolmasters with a national level trainer for a week or two at a time.