"With a few notable exceptions – like Facebook and LinkedIn – most companies that have started introducing IPv6 networks do so by running IPv4 and IPv6 in parallel, often with two different teams."
What is this supposed to even mean? There are only two types of IPv6 deployments that I've seen, dual-stack IPv4+IPv6 and IPv6 only (usually because of the lack of IPv4 addresses). Most of the top 100 sites are dual stack. What does "in parallel" mean?
Different teams? I've setup IPv4 and IPv6 peering with a number of different networks, and I've never encountered IPv6 run by a different team than IPv4. Do you have even a single example of an organization using different teams for IPv4 and IPv6?