I don't agree. I grew up (partially) before DSL, as did everybody before Gen Z, and I'm very thankful for it. I don't think always on internet is necessary for a fulfilling childhood. There's so much more to the world than the internet.
It's not if society is generally structured around that, sure.
But if the only way to find out what your homework is is a website, and that homework is posted as a multimegabyte PDF (this is how it's working for my kids, not a hypothetical), then lack of an available internet connection immediately affects your ability to effectively attend school, for example.
Now we can have a discussion about whether school is necessary for a fulfilling childhood, of course. :)
Sometimes I'm not sure that's necessarily a bad thing?