You not feeling lonely as a child doesn’t mean parents raising their children didn’t feel lonely.

Look at the date of the Betty Friedan book mentioned the article, or consider the Stones' song about "Mother's little helper" (valium) or, for that matter, Madame Bovary and Anna Karenina. All far predated the Internet or even the ARPANET.

Not long ago your social options were extremely limited. Today you can (roughly) be anywhere an 8000 square mile area within an hour, and talk to almost anybody on the planet within seconds.

Without the Internet (personal cars being a thing not long before), you were stuck with whoever lived within a mile or so, with "instant" communications limited to your neighbors - which was great if you liked them, and sucked massively if you didn't.

I'm oddly reminded of Victorian novels revolving around the notion "I dislike you and you're marginally ugly, but you're the only social option I've got so let's wed."