att knows their current speeds and competitors offerings in a market. they just aren't concerned.

my home town for example, only has 7000 people. but att is 100% DSL and the fastest speed they offer even if you live across from the central office is 5mbps. they did offer 6mbps, but recently lowered their speeds to 5mbps and forced everyone to resign their contract.

the cable company? had 5mbps in the 90s, then did upgrades until they finally reached 1gbps.

in my universities city, it is the same deal. except this town has around 25k people. the cable company finally reached gigabit speeds in around 2016. att is still 5mbps.

cable was/is the better technology(in comparison to phone lines) when it came to upgrades. so cable companies from the get-go had a leg up. meanwhile, ATT only has phone lines from the 1930s in many many large cities and never upgraded to fiber, which is about the only route ATT can go.