> have you seen parents at the bus stop, say, playing on their phones and not paying attention to their kids? (I say "their" but this is almost every parent, some time or other.) That's new behavior that didn't exist before smartphones, because it couldn't.

I saw plenty of people at bus stops or similar places with kids ignoring them long before smartphones. Sure, the use of a smartphone while doing so is new, but it doesn't fundamentally transform anything.