Picture two runners side by side: one in the latest super shoe, one in a decade-old racing flat. The difference is maybe one to two percent, not a completly different sport. A 3-hour runner doesn't magically become a 2:10 runner by lacing up. That's where your roller skate analogy falls apart, because skates eliminate the push-off entirely. The shoe still makes you run; it just returns a little energy on the stride. The training, the lungs, the pain, the will, all of it is still human. You're right that records fall, but the athlete is still the one breaking them.