When I started at the phone company back in the day it was post breakup. The waste that went on when there was no competition was sickening. Many of my co-workers told me about all the abuse and theft that comes with being a monopoly - with the cost being passed down to the customer and the tax payer.

Also the world of the Internet, the openness of IP protocols disrupted them. They finally had to deal with technology that wasn't dictated and controlled by them.

We lost lots of good paying jobs, we lost the rollout of ISDN, which would have spend up offering high speed network access, we lost hundreds of millions spent on basic research.

We gained, a bunch of openness, mobility, and access to a wider breadth of services. It's still a mixed bag.

All of the early core ISPs like UUNet and its competitors, in the pre 1997 period.

It is worth observing that the quality of DoD acquisitions and public-funded R&D also declined around the time of Bell's most recent breakup.

Might there be other forces at play than the dissolution of a single company?

You might instead ask if society was better off before the invention of the teenager. That was emblematic of the shift toward short-term-profit-driven thinking we now call neoliberalism. That economic philosophy also happens to stifle innovation of the Bell Labs type by not financing long term projects.

Today monopolies exist in spirit if not in technicality. Does society benefit? I'd say that looking back longingly at Bell Labs means no, it doesn't.