You can run v4 and v6 side by side easily though -- they work pretty much the same way as each other, and that's the standard deployment model. From an end-user

You can run v4 and v6 side by side easily though -- they work pretty much the same way as each other, and that's the standard deployment model. From an end-user perspective, there is no difference: you go to Google, search for "facebook" or whatever and click on the first link. All of this happens over v6 in exactly the same manner as it does over v4. As for v6 autoconf not working exactly the same as DHCPv4 does, it's not like they purposely ignored it. Remember that DHCPv4 was being standardized at about the same time IPv6 was, and it wasn't really ubiquitous until a good half a decade afterwards. The RFC for router advertisements in v4 was published two years before even DHCP was, and there were various other ways of doing autoconf. It's not reasonable to expect them to have known that DHCP would win.