I'm going to go out on a limb and say that a huge chunk of musicians - certainly throughout history and still nowadays, although possibly less so, because of how commercialized modern music is - are either AS or heavy on the awkward/eccentric/talented character. Put it this way - you don't get to be a master guitarist/pianist/etc without long hours locked in your room doing the same thing over and over again.
With Mozart, Beethoven, etc it is blatantly obvious that they were AS, any description of their personality can point to that. Back then, the societies they were in recognized their gifts from an early age, found the place for them, and knew that the way that they acted was a symptom of that incredible gift, putting up with it was not a problem. Their work was more important than their image.
The mass media has changed that and made image more important. First of all, the legendary composers were way more autonomous than the big-name musicians of today. The composers wrote their music, from the heart, (the only way in which they knew how and were expected to) for managed performers to play, whereas modern music is basically written by and for the pursuit of profit and played by well-managed singers, guitarists, etc who in all actuality have a suspect role in the music they are so well known for. It is much harder to tell who they are at heart because not only do the record labels, music critics, etc have all the say in "their" music, they also control their media image, which is used to sell a certain shallow lifestyle to the public. Aspies aren't known for business approaches to things, not known for taking orders so readily, and most importantly not known for public image - so our role in music has probably declined since the 1960's. And that's just looking at it economically. I could get more into how the manufactured music of the past 50 years maybe part of some agenda that the mass media has - MKULTRA, Jim Morrison's dad, Laurel Canyon, etc - but that is when the claims shift more towards accusation.
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"Psychic kids, try to understand who made them this way, so they don't feel bad...floating in space, the ghost is out there, so you're not alone, only out there"
Sagittarius, ISFP, diagnosed with AS when I was 13.
http://www.last.fm/user/DolphinCove