Actually, his idea was to extend the IPv4 to become IPv6, so that v4 is included in it. This is what happens when you run a DOS program inside any NT based Windows. You are not really running on DOS, it just looks like it to the program.
And given that all the software would have understood 16 byte addresses by now, the transition would just happen.
Practical example: my home network would have been on IPv6, although all my addreses would still be written in 4 byte form in my config files. My effort in this: zero. ISP effort in this: close to zero.