“However, I wonder whether we have reached the point to where NOT being on Facebook would be considered a ‘negative’ by a potential employer.”
Yes...because obviously you are anti-social.
For that matter, what’s to keep an employer from requiring you to open up your privacy settings so they can see it?
The company I work for has a policy that says you can’t say anything about them on social media without permission, although I don’t think they’ve ever tried to enforce it. I don’t talk about my job and I’m not friends with any of the clowns from work anyway.