So there's talk of "balance" and then there's this:
"As one high school girl described the paradox to me: we’re the most connected generation in history, “but we suck at intimacy.”
That's a "high school girl" talking people. (I'm not challenging her feelings, but I would challenge her perception as fact and add that her perception is likely colored by adolescence. She may be right, but how would she know? We aren't shown. So her comment becomes an emotional appeal, valid as long as you don't let it frame the conversation)
There's a blog post by the last psychiatrist (long read btw, very contrarian) that takes a different perspective to the problem http://thelastpsychiatrist.com/2014/01/randi_zuckerberg.html
I don't agree with all of his conclusions but I like that he challenges the premises, especially this one, where we've all somehow accepted this idea of being "plugged in" as the default and that all we have to do is find the right balance, and why? Seems to me because its comforting, you don't have to feel guilty about being plugged in if everybody else is doing it, you just have to find the right "balance". But as other commenters have already said, this isn't true, at least not true everywhere and certainly not as pervasive as its made out to be.
So, coming from that point of view the biggest problem I see with the book as its presented in the review is that it seems custom tailored for people who are already too plugged in and by assuming this to be the normal, can offer no way out. Maybe there is no balance, maybe "plugged in" isn't normal because maybe, just maybe "plugged in" doesn't mean "being distracted by technology", maybe it really means "being a dick" and there's no real balance to be found there is it?
Now I'm not saying there isn't a problem to be solved, or that the author or the reviewer are being disingenuous, or even that there isn't an answer. I'm just saying that if the premise goes unquestioned, then this makes the conclusions problematic.