My mom always talked about the party lines growing up in Florida in the 60s, and how she could never get a call out because “Barbara Snyder talked too much and always tied up the lines” lol. Apparently it was common for one party line per block or something like that. Iirc it wasn’t too common to have a private line until much later, as the phone company had to run dedicated lines back to the central office and it didn’t always happen until much later.