IPv6 is a slightly different model, different enough that you can't just copy the configuration from IPv4, and that adds a significant implementation burden. If

IPv6 is a slightly different model, different enough that you can't just copy the configuration from IPv4, and that adds a significant implementation burden. If IPv4+ had been created instead, we'd probably all be already using it. That said, it's obviously way too late to go that direction. The only successor to IPv4 is IPv6. Choosing the wrong model just made sure we'd have to go dual-stack for a loong time.