In the wild, the horse breeds are usually much purer than domestic horses and ponies. We as humans, have tried to create perfect specimens. If they look nice, move well, jump high or run fast we breed with them, despite their dental problems. Also, horses in the wild will eat for up to 18 hours per day, moving across different terrain and soil types, unlike the horses we keep for our own use. Lastly, if a horse in the wild had poor dental conformation it would not survive and therefore it would not be able to pass on it’s poor dental genetics.