Life happens. Your wife falls and breaks her wrist. Your mom has a heart attack. They want you now, not when you deign to look at your communications. And until you do look, you won't know if it's that she broke her wrist or that she had a heart attack.
If you are disconnected enough from other people that nobody has a valid demand on your attention, then you're part of the problem of social disconnection.
People usually can wait. For the rare case where they can’t, there are even ways to poke through Do Not Disturb mode.
IIRC iOS also has a feature which allows through someone who rings multiple times in quick-ish succession?
Responding to an ambiguous worry of an emergency that may never even occur during your lifetime by allowing yourself to be continually interrupted by spammers (traditional call-based and new app-based) is actually a decent illustration of the overarching societal problem.
The straw that broke the camel's back in this case was the behavior of the Messenger notifications. They filled messenger with so many bullshit "friendaversary" and other notices that I stopped paying attention and I missed my real, actual friends who were trying to get in touch with me. Such a transparent Skinner box, I couldn't respect myself if I went along with that kind of manipulation. Then when I found it's basically impossible to disable Messenger it became clear that I had to delete it all. I'll download my data from them and call it a day.
It's such a shame because Facebook put me in touch with a number of people that I only sent a Christmas card to, if at all. But I think the nature of these social networks is that the more addictive and manipulative ones quickly crowd out the decent ones. Metcalfe's Law seemed like a great thing until you realize that the growth has to be exponential to have a chance of "winning".