I understand it is a popular theory, but I just have a hard time believing that humans would be able to hunt horses to extinction in the Americas, without even

I understand it is a popular theory, but I just have a hard time believing that humans would be able to hunt horses to extinction in the Americas, without even a small reserve of them remaining and then repopulating. The current estimate is less than 1M people spread out across the Americas around 10k BC...I just don't see how it could happen. It seems like larger climate change may have been the reason humans start going to America, and also leading to the horses demise.