IIRC, lots of other companies selling telecom use AT&T infrastructure (infrastructure owned by AT&T now, not infrastructure built by a different company called AT&T in the past.) There are a much greater number of companies that you can buy local and long-distance service from than companies that actually operate the physical infrastructure.
I suspect that current infrastructure is the "AT&T switches" that are relevant here.
I suspect that current infrastructure is the "AT&T switches" that are relevant here.