In the early days of 5G, AT&T seemed like a disruptive force in its own industry. It established its Domain 2.0 initiative in advance of 5G, to shake up its supply chain in support of software-defined networking and future 5G virtualized networks. Admittedly some of its more interesting vendor selections, such as Tail-f, were promptly acquired by incumbent suppliers (that acquisition got Cisco a place in Domain 2.0), but AT&T continued to work with innovators, such as Barefoot Networks (now part of Intel), to push forward its SDN agenda. Meanwhile, it was contributing heavily to open and open source activities under the auspices of the Linux Foundation, Open Compute Project and Open Networking Foundation, and even setting up…