That simple regression does not indicate anything...the author does not show that the data follows an exponential; he just imposes it. What about a non-parametric regression? What about structural breaks in the time series?
Of course, it would have also implied that by the year 3000 some guy will be finishing before he starts, but from the data given that's no sillier a conclusion than the one given.
PS. Seriously though, well done Mr Bolt. I'm not usually impressed by athletes, but this guy really seems to be way out of the norm.
I'm not saying Bolt is a User, but I think it's safe to say he's applying every advantage available.