Verizon decends from Bell ROCs, but not from the national AT&T company.

Current AT&T is the result of Bell ROCs buying out the national AT&T company.

But it's not the same company at all. The commitment to reliability is gone, the full vertical integration is gone, the monopoly revenues are gone. The market for phone calls is quite different as well.

It's a shame to have lost reliability and the increase in latency for audio is objectively bad and I don't know if we'll ever get back to near zero added latency on phone calls. Otoh, telecom competititon has driven much more capable and less expensive offerings, when they work.