It seems to me that the original purpose of this thread was to rationalize someone's current drug use by pointing out similar (alleged) usage in a folk hero. I agree that this is silly. Let's take the logical extreme and assume that Pre smoked an ounce every day. Does this in any way tell us that he ran well because of smoking dope? No. In fact, one would have to wonder how well he could've run had he not taken part. We have no data one way or the other, thus, whether he did or not is of no consequence to us regarding our current training.
What matters is what we can do today to improve. Rationalizing is for suckers.