I don't think the Walkman is a good comparison at all. Instead, look at the boom box. Big headphones today, or the Walkman in the 80s didn't invade someone else's space. They allow a person to withdraw. Boom boxes, and Google Glass, on the other hand, are explicitly outwardly focused. They force your presence upon others.
You clearly haven't used Google Glass. With the exception of the camera, everything is inward focused. Everything you do and see and interact with glass happens with only visibility to you. Nobody else can see what you are seeing. I wouldn't compare it to the boombox at all.
With the exception of the camera...
The camera is a large part of what people are objecting to.