Comment by kemotep
Any solution that requires updating clients, servers, and networking equipment to support the protocol and/or adjust the network address scheme of the environment will require the exact same steps doing an IPV4 to IPV6 migration would require.
Not so. IPv4->6 removes all existing v4 address blocks and redoes the addressing scheme. Those changes weren't necessary for expanding the address space. This implies that day 1 of using ipv6, all your addresses are different (and way longer), all your routes change, DNS DHCP etc all need to be swapped out, and bans/reputation are all reset with no clear replacement. And there were a bunch of smaller changes / new features.
Whatever you do to get more addresses, it will look similar in the end, but the steps could've been very different.