At some point they told the Telcos you have to offer competition. So a dozen different budget phone services popped up over like the last 15 maybe more years. They all have decent rates and use one of the big 3s infrastructure, so they get the same service levels.

The big Telcos still exist because people don’t fully understand how the competition works and because people always want the newest iPhone and are bad at math and calculating risk. So they are in a perpetual contract so they can get a free “insured” iphone of the latest variety, while only paying 3x for their cell bill.