If I were a dictator I would just put a deadline on it. January 1 2027: IPv4 forwarding is turned off on all core routers.
You can still use IPv4 internally if you have legacy devices, but anything on the Internet has to use IPv6. You have about 5 years to get it done. There are lots of solutions for specific use cases including stuff like ::ffff:1.2.3.4 and IPv4/IPv6 NAT devices. Most of which won't be as necessary as people think because IPv6 support is already widespread everywhere except ISPs.
You can still use IPv4 internally if you have legacy devices, but anything on the Internet has to use IPv6. You have about 5 years to get it done. There are lots of solutions for specific use cases including stuff like ::ffff:1.2.3.4 and IPv4/IPv6 NAT devices. Most of which won't be as necessary as people think because IPv6 support is already widespread everywhere except ISPs.