> the Tarahumara (ancient running people) are the best distance runners on earth

Pretty sure the Kenyans, Ethopians, etc. might have a word or two to say about that.

More importantly, the emphasis in "may be counterproductive" should definitely be on the first word. Actual real-world results haven't matched the theory. Sure, there will always be someone to provide anecdata about how they switched to minimalist running shoes and it was great. The ones who switched to minimalist running shoes and either injured themselves or didn't see any benefit and switched back tend to talk a lot less. Statistically it's a wash, and ends up being pure personal preference. People who run poorly will improve exactly enough to make up for the difference in shoes, and no more.