Alexander the Great's impact on art? On the individual?

The reason I ask is because of all the things I've noticed about Greek art, one of the most salient is the noticeable lack of portraiture in the Greek artistic tradition. During the life of Alexander and even after his death, however, there is a noticeable increase in actual portraiture -- and not just of Alexander, either. His successors ended up putting both their portraits and Alexander's portraits on the currency they circulated, and Hellenism itself is, among other things, typically regarded as the birth of the Western tradition in portraiture. All of this is virtually absent prior to the rise of Alexander, however, with only a couple smatterings that hint at portraiture but don't constitute anything particularly significant.

Might this signify a larger impact that Alexander had? If portraiture requires an interest in the individual in order to even exist, did Alexander perhaps impact the way people view the potential and the efficacy of the individual? His accomplishments were unprecedented for his time, after all -- practically the sort of stuff you'd only find in legends; since he was the first individual to accomplish something of this magnitude, might this have impacted the way people look at the individual as an agent of change and ambition? The rise in portraiture -- at least in my mind -- seems to support that, but I haven't been able to find anyone else who has anything to say on the matter. Help?