I'm afraid this is not the case. At all. Just the wishful thinking of those who hope for a justification to their free sharing wishes, like saying that sharing music or anything on the Internet leads to more people buying the original. It doesn't.
Gibson made its fame in a time when it was not heavily copied. The Les Paul was made into an icon by Clapton and his colleagues in the mid 60s, who bought them used when they were no longer produced after going out of fashion. They had been in the lower half of the price range all along, by the way, just like the Strat', which is why they became popular while the more expensive Gibson and Fender models remained more marginal. The same Clapton also bought his Strat's used and I suppose Hendrix did just the same (or you'd think he'd bought left-handed models). Copies of these models came long after the fame, of course, sometime in the 1970s.