MaBell was a weird monopoly that broke some rules about how monopolies were supposed to act. They weren't Wayland-Yutani tossing peasants to the xenomorphs.
Monolithic to the extreme, they were supremely vertically integrated so that there was virtually no part of their system that wasn't made, controlled or specced out exactly to what they wanted.
Certainly their labs were designed to make their processes better to further their business, but it a bizarre and I'm sure unintentionally altruistic way they believed that research into theoretical physics would lead to a better way of doing things. This led to the laser, the transistor, UNIX, and they discovered the very "song" of the universe, among a host of other things.
Their list of Nobels, Turings and IEEE prizes would make any university blush.
Yea, it cost money, and your phone bill wasn't cheap. But you picked up the handset, and you had a dial tone every time. Their idea of robust infrastructure and "uptime" was in a league of it's own.
I'm sure they had some mean practices, but they seemed to keep it under wraps.