Actually, IPv6 wouldn't be required to have all appliances in your house be internet-ized. Just like now (IPv4), only one
real IP address is required when you have a NAT capable router between the internet and your private IP-based toiletry network.
The reason we haven't reached critical mass yet is because the number of devices that
have internet access, isn't in a one-to-one ratio with the number of IP addresses
available.