Agree with everything you said except for this last bit:

> If you're a football player or a film director, add drugs probably won't do much.

It's obviously not a useful data point, but my own personal experience is that my physical endurance is greatly increased on the days I've taken my Adderall prescription.

If you read up on amphetamines, it's pretty interesting. They known to provide significant physical enhancement in a number of dimensions. The trick is keeping the user from developing a physical dependence.