It's a fair point. Here's my anecdote: I use Facebook solely via my "spouse firewall"; that is, I don't have an account or use it, my wife just lets me know anything I need to know about through it. She is probably a straight down the middle average Facebook user; daily-but-light use, has learned just enough to squelch people she needs to squelch, the standard mix of friends, family, and old high school co-attendees, etc. The only priming I've done is to remind her that you shouldn't allow Facebook to have the canonical copy of family valuables; upload whatever photo and video you like as long as we still have the originals somewhere.
She's definitely been getting increasingly frustrated by their grabbiness, and has been coming to me with stories about Facebook and privacy on the Internet. Granted, that's because she knows I'm interested, but we don't move in the same circles online, which means that these stories are indeed penetrating further than just the HN bubble. She's nowhere near ready to dump the service yet, but the idea is clearly thinkable.
(Anecdote? Certainly! Let me know when you figure out how to run a repeatable study on this topic.)
To be honest, if Facebook IPO'ed tomorrow, I think I'd pass. I'd probably miss out on an initial increase, but I bet in 2014 Facebook will not be as dominant as it is now, and their growth (not their survival, but their growth) depends on that not happening.