Over the past few years, AT&T has undertaken one of the most ambitious attempts at transformation seen at any major operator. It is, in parallel, seeking to up-end its cost assumptions and supply chains in order to phase in an entirely new structure, in its network and its organization. It has also been leveraging its inhouse developments to drive open platforms, in a bid to get wide operator support behind a multivendor, cloud-based network that could support new cost models and service agility. And it has not just focused on its fiber and 5G evolutions, but acquired companies to extend its business laterally, notably DirecTV and Time Warner; and formed strategic partnerships to support its cloud strategies. Now it is…