Do you see Glass as "the future smartphone"? Assuming Glass was readily available for $500 a unit, at what point in your life do you think you would buy it? i.e., "I would buy it as soon as I had $500," "I would buy it when I had a comfortable job where it wouldn't take me too long to save up $500," "I would buy it if they had installment plans a la most smart phones and I paid a monthly cost," "I would buy it when I was making enough money that I could blow $500 on an item and not really miss it," so on.
I don't think anyone regards Glass as "the future smartphone." It isn't a smartphone. It's a wearable interface which allows you to interact with your smartphone when your phone is in your pocket/in your bag. I would buy it if I had money to blow. It's not a gimmick, but it's not something that is necessary for my life. It would just be very cool to have, but at this stage of my life when I'm going to school almost every day, I just don't have the time/resources to do anything cool with it.