I don't know how you get 10 lengths in 2 seconds. I'm not questioning Secretariat, just the field he ran against.
It's the Wilt Chamberlain type of debate.
It's a very different debate because you can't compare "points" sports with "time" sports, and the comparison here actually strengthens the case for Secretariat.
Secretariat put up the best time in Belmont history AND the best time in Preakness history AND the best time in Kentucky Derby history,
without a great deal of competition (at least in the Belmont -- the runner-up in both the Derby and the Preakness was Sham, which by all accounts was a horse-of-the-year talent)
. The question is whether he would have done even better if pushed by the likes of Affirmed, Barbaro, American Pharoah, etc.
Wilt, Babe Ruth -- that's totally different. No doubt they would have dominated, but Wilt wouldn't have averaged 50 points a game. His numbers would be worse in today's NBA. Secretariat wouldn't be slower today.