The AT&T breakup destroyed the telecommunications industry. AT&T’s gold-plated POTS network was expensive, but for its time it was a technical marvel. Competitive industries don’t build stuff like that. There is a reason Apple and Samsung (huge, vertically integrated monopolies) produce the best phones.
Comparing one very effective and interesting skunkworks lab with the incredible explosion in choices and service in telecommunication, as well as drastically lower prices, that came when the monopoly was broken up?
I think you're demonstrating the anti-monopoly point handily.