> And if they need to expose some service to the internet, they'd need to punch a hole in the firewall--which is exactly the same dance you'd have to play with port forwarding.

The difference being, with IPv4 only one machine in the house can have a port open. You don't just open a port, you choose _which_ single machine gets the port. Sometimes you can't open a port on a machine because the port's already taken.

With IPv6 any/every machine can have the same port open at the same time.

One of these scenarios is obviously just broken.