[perennialmind]

As I recall, 6to4 worked beautifully between 6to4 nodes in the absence of middlebox interference. The fatal flaw was the anycast address for accessing the "real" IPv6 network. The rosy outcome imagined in the article doesn't require a hypothetical IPv4 extension: just the novel idea of leaving the IPv4 core alone and extending the edge - which would have brought the financial incentives into alignment.