People need to read better. He said that drugs make it possible for athletes to have close to peak performance through-out the year, not that very good numbers are impossible to achieve with-out drugs in general. I personally believe that it is unlikely for top athletes to be clean at important competitions. Even if nobody would dope, but every top athlete believes everyone else is doping, suddenly it will be very hard for that individual to NOT take drugs for say the Olympics, which might be a once in a lifetime opportunity. Of course every other top-athlete will believe the same and suddenly nearly everyone is taking drugs.
Sports competition, in the final analysis, is just a more cultivated form of a battle for resources (material and immaterial), that has been happening in our species and in other species for millions of years. The modern human mind is able to create boundaries and rules for this battle, but whenever there is a way to gain an advantage by breaking those rules, competitors at the top will be very, very hard pressed to do so. Those people are not like the majority of people posting in this forum for whom training and sports is a more or less serious hobby. This is their career that they work for every single day for multiple hours just like we spend that time in school or work to succeed with our resource-gathering strategy. The difference between the two is that professional sports is very unforgiving and there is little place for average performers - unlike in many other fields of human life today. Top athletes make it their life goal to succeed and the way this is done quickly becomes secondary.
So no, I do not think that he is exaggerating at all.