My theory, The Spanish/European being sole or original source of horses to the US is wrong.
The Nez Perce and probably others had horses before the Spanish showed up.
The escaped spanish horses populating the west is wrong.
The tribal horse cultures of the west originating solely from escaped Spanish stock is wrong.
Historical tidbits to back this up.
History books are notoriously racist and nationalistic. Lots of what we learned in US schools is total BS and leaves out alot. As well as a tendency for everything to be attributed to white people and Americans.
Columbus "discovered" America, a land occupied by millions,
Americans defeating the Nazis,,, yeh migh wanna look at Russian history, and on and on,,,
More and more Asian and African precolumbian contact seeing the light of day. Seems Egyptian pharohs liked their smoke and blow, Chinese artifacts in CA,,,, and frikking Pueblo's that speak a dialect of Japaneses.
Ok someone look at old school Appaloosas and Nez perce photos or drawings, Now look at a picture of Spanish horses, and a picture of central asian horses. Doesnt take a rocket scientist to see where those horses came from. Even today when the Nez perce have tried to restablish their breeds based on old photos and descriptions as well as some head of supposedly maintained stock. They went to Afganistan for breed stock NOT Europe of to other US breeds. Look at old Han dynasty chinese paintings of their horses, now look at an old stock appaloosa.
The Chinese, Japanese, Koreans, Polynesians, believe it or not all had the ability to make ships and boats. But we are to assume only white people crossed an ocean ? Especially ones with currents that would make it even easier to hit the Pacific Northwest than for Europeans to hit the Northeast.
SO by 1804 Lewis in Clark found a tribe that was already famous for horse breeding and had even developed their own trademark breed, yet we are to believe this was a result of enough horses getting loose in mexico starting in the 1500's walking through thousands of miles of country inhabited by tribes whos first inclination when seeing horses was to eat them. Seriously horses woulda been mega hard to get to the Americas, You honestly think people would just turn em loose willy nilly ? Then they travel through mountains outside natural migration routes, and stumbling upon a tribe of people with little recorded european contact prior to 1804, SO all that was going to happen in less than 250 years ?