There are a lot of Americans concerned about this, in my opinion. However, most Americans go to work, get home from work, eat dinner, surf the web, watch tv, mow the lawn, pet their dog, play with their kids, and go to sleep like it's just another day, same as the prior and same as the next.
The NSA is currently doing very little to physically intrude on the lives of the typical American. Like most people, if a threat isn't in their face, they generally will not respond to it. So it doesn't seem real (making it very easy to cower in fear and avoid confrontation, with statements like: I have nothing to hide), and by the time it does, it'll be far too late to stop it.
I agree--most Americans have probably been going about their lives and not paying too much attention to this so far.
But I think this issue is going to be in news cycles for quite a while. The more news cycles, the more likely people will start to think about it, the more likely they will run into the friend who feels passionately about it, and the more likely they are to decide it doesn't belong in their America. (Or that if it does belong in their America, that it shouldn't be kept a secret.) It's important for those who feel strongly about this to speak up now.