While I don’t necessarily disagree with your point about using heavy sleds as a primary means of speed development, I think its a flawed argument to say that since we don’t see freakish 10yd times, the heavy sleds are a waste. It is entirely possible that the sleds are capable of making mediocre 10yd guys into good 10yd guys or good ones into great ones but not necessarily push the absolute window of performance into the freak realm. This is no different than any other training modality which can be useful by all counts without being responsible for unbelievable performances but rather adds to the training and helps affect moderate increases in ability.
Ian, your response has a lot of holes. Just because something works, doesn’t mean it’s a good option. Lot’s of things work. It’s what works better. We are trying to push the absolute window! Hence records and personal best times. Freak realms are evidence of what works since any high school kid will get better from nearly anything.