To say that the leg speed of a person has no relevance to his ability to kick is as idoitic as saying You could smash gatlin over the last 200m in a 5k. First of all, you need to reevaluate the term "kick". It is not stumbling home, struggling to finish. A true "kick" has to resmemble some sort of increase in the race pace, because if your running 40+ seconds over the last 200m, that is not a kick by any means. Dont confuse the term "kick" with just the last part of a race.
It is obvious that you need to be conditioned to be able to kick, but that doesn't take away from the fact that most of the best kickers are the racers with the quickest sets of legs. There are ways of taking people's kick away from them, much like El G did in Athens 2004, but if he left it down to a pure kick, he woulda got squashed just like he did in 2000.