There are a lot of historical examples of people running relatively fast off of low mileage.
But what is often left out about the praise of low mileage is one of few things. Either, one, the runner developed his training to run more miles as they progressed. Or, two, other training methodologies that developed subsequently in the course of track history had greater success. Or, three, people often ignore the genetic freak of nature that the athlete may be and may just be an outlier that never needs much volume of training.
Evan Jager ran around 35 mpw in high school and was a top runner just after one year at Wisconsin before following Schumacher to go pro. And he didn't make a big jump in training. He was brought along slowly and much of his workouts in college were shorter (less volume, less reps) than the other guys at Wisconsin. Obviously, Schumacher had him do more in subsequent years.
Emma Coburn was a state champ running approx. a 5:05 mile at altitude but maybe running 20 mpw in track season, but also doing volleyball and basketball as opposed to xc and winter track. Obviously Wetmore progressed her slowly, but she was probably doing 60-70 mpw when she was done at Colorado.
Sebastian Coe is great example of how people ignore his high-mileage base. His books mention about doing 80 mpw during xc season to prepare for track season. And 80 mpw is a lot of mileage for an 800m runner! But people focus on his mileage during track, which was considerably lower.
Sure, Roger Bannister ran sub-4:00 and probably rarely, if ever, exceeded 50 mpw. I think I read he ran a sub-4:20 only running twice a week. However, plenty of runners that followed him ran way more miles and ran faster. Lydiard's runners ran way more and had faster times. Ryun ran way more and had faster times.
But I think the question will always be what is optimal training as opposed to good enough training? And what are the trade offs?