We already have the best upgrade that's actually possible given the design of IPv4 -- the fundamental problem is a combination of the pigeonhole principle (whic

We already have the best upgrade that's actually possible given the design of IPv4 -- the fundamental problem is a combination of the pigeonhole principle (which means there's no way to allow unmodified v4-only hosts to talk to v6 hosts) and the fact that there's nobody in a position to force people to use the necessary modifications. As a result, we end up with several generations of hardware that support everything necessary but where the people who wrote the config for them are too lazy to actually turn it on.