Years ago I owned a 15h purebred Arabian mare imported from Russia that had a natural Park gait ( not quite as high as "trained" horses but almost as high front end steping )These beautiful, gentle horses have been abused to make them lift their hooves up high. It is illegal now, but it is still done.
https://en.wikipedia.org/wiki/Soring Look at the picture of the X-ray which shows mails in the thick pad for more weight. Think maybe it might be uncomfortable for the horse to wear those?
This is a good article and has lots of pictures that show what is done to the horses for the show ring.
https://www.avma.org/KB/Resources/Reference/AnimalWelfare/Documents/Soring-Bookiet-March-2014.pdf
I love Tennessee Walkers and have never had one that picked up their feet in such an exaggerated manner. The smooth gait is natural to the breed, the tucked down rump and super high step is not. Pretty to look at? Yes, until you know the real truth behind it.
Not just any horse is gaited, nor can you take a horse that is not gaited and teach them to be gaited. There are several breeds that are gaited, Tennessee Walkers, Missouri Foxtrotter, Rocky Mountain, Paso Fino, Saddle Horse and several others.