Local telephone service wasn't always a monopoly, pre-1996.
Ma Bell's patents expired in the 1890s. "Independent" telephone companies sprung up all over, including in the cities where "Bell" companies operated. Strowger invented the dial in 1896 and independents started adopting it, but not Bell. Nowadays many of these would be called CLECs. BUT there was no obligation to interconnect, so an independent phone, like from Keystone (in Philadelphia) or Granite (in Quincy) would not be able to call a Bell phone. The "network effect" worked against them.
Over time, some of the independents in Bell areas were acquired by Bell, and some went out of business. Keystone was a holdout (I think until 1929). In 1912 or so the "Kingsbury" agreement allowed independents to connect to AT&T Long Lines for long distance calls, though there was no obligation of local interconnection. It also banned AT&T from acquiring independents who weren't bankrupt, thus leaving most rural areas in independent hands. This was the patchwork monopoly system (many local monopoly carriers linked by AT&T toll) enshrined in law in CA34.