Baloney. Check out the horses that run freely...... if you can find any of them any more.
You are merely making excuses for a meaningless, human-centered sport......... horse racing.
Horse racing is a lame and poor joke.
With some exceptions (where the breeding stock is varied, sometimes by deliberation introduction of a good stallion) they are pretty weedy and weak - and in some cases showing signs of severe inbreeding. Left alone, feral horses tend to revert to a small, short-backed, big-headed type.
I'm very familiar with the feral horses on Cumberland Island and have spent some time photographing them. They don't look like what you probably expect wild horses to look like. "Scraggly" is the first word that comes to mind. Many have very noticeable conformation faults that interfere with gait, etc. But the faults don't prevent them from breeding . . . so over time with the limited gene pool you tend to get some ugly and unsound critters. University of Kentucky vet school DNA analysis of wild herds has turned up low foal survival rates, blindness, and dwarfism in feral herds with little genetic variation.
Selective breeding, by humans, has given us a wide variety of horses suitable for various uses. Without human intervention, horses revert to a feral type that isn't much use . . . other than to wander around. Just like dogs, left to their own devices, revert to the "Carolina Yellow Dog" type.