Interesting point.
However, drugs in sport is little more than cheating. Also the whole life style is based on fitness, which drugs certainly do not represent.
Rock stars etc, although role models to a degree, are hardly a picture of health morality.
Don't get me wrong, I abhor drugs in every guise, but that is the way of rock and roll. And as you say dates back to The Beatles over 45 years ago.
I may be wrong but can not recall a doping offence amongst sports stars that far back.
Does drugs free the mind for creating better songs??
I don't know, I have never done drugs but I would probably say no. David Bowie, for example, has knocked out decent tunes at the height of his coke habit as well as after he was completey clean.
Winehouse is an interesting case. Personally I love her music so time will tell when she finally gets her act together and becomes clean.
Doherty is simply crap, heroin or not. He really is a waste of space and deserves all the negative press he receives.