AT&T / Bell was broken up in the 1980s into multiple entities. Splitting local and long distance services resulted in significant competition for long distance, while local phone service remained / remains heavily regulated in many markets. Here in Canada I remember having to pay $0.34 per minute to Bell in the 1980s to call a friend that was a 30 km drive away. Overseas long distance was in the dollars per minute ballpark.

This wasn't without some losses. Bell Labs lost a lot of funding once the Bell monopoly was split up. The amount of R&D that the telecom giants funded over the years resulted in massive public benefits, creating the tech industry we all know and love.