I have been giving this some thought.
In the late 50's and early 60's, when I was a boy, we didn't have a phone and I didn't know many people who did. And yet my friends and I always managed to meet up on the Harbour or the Park, where we lived in Watchet, Somerset, every day after school and at weekends, without making any prior arrangements at all !
Tea parties, for birthdays, etc. were arranged and invitations were sent out by postcard, and everybody seem to turn up on time.
Important telephone calls were made from my Grandmother's phone ( she was quite posh ! ) but all others were made from the telephone box on the corner.
Don't get me wrong....I wouldn't go without my Mobile and PC these days
( and the loss of my Broadband today is driving me nuts ! ) But we seemed to manage OK years ago. But there again, our lives were so much simpler then !