A very good point, my age is showing. Personally, I can't imagine a world that isn't connected (even when I was a young kid, my dad had a pager and my mother had a brick cellphone for work).
In all fairness, cell phone coverage is still pretty spotty in national parks, wilderness areas, etc. And I, for one, don't buy WiFi on planes, in part because I appreciate the time as an opportunity to read books and watch things I often don't have uninterrupted time to.
But, yes, as you see on this thread people are growing up today who find the idea of not being able to be reached or to reach someone (even for a few hours) as unsettling. And, if I'm being honest, I've also thought to myself that if I were going off on any extended solo hiking/backpacking these days I'd start seriously thinking about getting one of those satellite messaging systems.
People should learn to not be anxious of having no connectivity. Self-reliance used to be a thing, and while its inconvenient when you don't have connectivity, it should not cause anxiety.
I think there are circumstances where it's prudent, when reasonably practical, to have the means to summon assistance if things go sideways. However, you should be as prepared as possible to fend for yourself and, as you say, I find it almost bizarre to be anxious/fearful/freaked out just because you're separated from your smartphone.
ADDED: My concern is that there seems to be an increasing expectation that, if "they" don't make cellular coverage available everywhere they're creating an unsafe environment and something needs to be done about that. (And conversely, if I'm not always available, I'm being somehow irresponsible.)
It was a glorious time when you couldn't get connectivity in flight or in national parks. The tether has never been tighter.