Roger Bannister was far from ordinary in his time. High school runners can run 4 minute miles today, mainly because they have the benefit of knowing how to properly train, thanks to all previous athletes and trainers that came before them. The metaphor "Standing on the shoulders of giants" comes to mind.
Interestingly, he probably wasn't the first person to run a mile in four minutes:<p><a href="https://en.wikipedia.org/wiki/Four-minute_mile#Possible_other_claims" rel="nofollow">https://en.wikipedia.org/wiki/Four-minute_mile#Possible_othe...</a><p>Probably none of the previous cases is sufficiently well documented to be recognised on its own, but there are several cases that are 90% certain, or thereabouts, so probably at least one of the previous cases - there are more of them than the three mentioned in the Wikipedia article - did involve someone running a mile in four minutes. There's a whole book on the subject, I think, but I can't remember the title.