Another interesting angle related to their coming from money—I don't have enough data to really even call it, well, data, but the limited glimpse I've had into properly upper-middle (as in the Fussell, social-class sense, not the "I make $130k/yr as a middle manager and live in a McMansion in a nice school district, so I call myself upper-middle class" sense) and upper classes' kids and schools, they're giving their kids phones
way later than the public-school set. Like, 20% or less the ownership rate by 5th grade, I'd say. Nowhere near universal personal smartphone ownership by 8th grade, even, unlike the public schools, where nearly all the kids have one by then.
But I'm mostly seeing a single school, so it may just be that that school operates in some kind of techphobic bubble, not that the better-off are generally exposing their kids to cell phones and the Internet way less than the middle-class and lower.
... then again, maybe what I'm seeing isn't a heavily biased sample, and that's exactly what's going on, and this article is a manifestation of a real tendency of the upper classes to curtail tech exposure for their kids, compared with the general population.