Ha, not only that, but Usain eats like shit and parties hard. Plus, he has atrocious form on his lifts.
Meanwhile, scrubs with lesser talent can track every molecule that enters their mouth while expert coaches correct every millimeter of movement in their lifts and still never come close to Usain's times.
Do you really think thousands of bodyweight squats is a more productive use of one's time than squatting 600 "for a few reps"? Not that I think bodyweight squats are completely useless- they serve their purpose as a warmup to real squatting or as rehab/prehab. But you're testing the limits of diminishing returns here. If you wanna condition your legs, go push a sled or do some sprints.