Many years old routers had a single external ipv4 and behind the NAT each computer got an internal ipv4 as a way to never end up exhausting the pool of IPs that each ISP has. But it’s been a long while since it has changed:

Most of the home networks I use are still behind a NAT use a single ipv6 to interface the world and within the network each computer has an internally assigned ipv4 just in case some operating system may not be compatible with ipv4.

Still are many old routers using ipv4 only out there as not many people care to renew their hardware as long as their WhatsApp and Netflix works.

Well, if governments really care about IPv6 (and the previous campaigns to push it were not just about "look how progressive we are"), they'll do something similar to what they've done with digital TV broadcasting :

they would first ban the selling of new devices not compatible with IPv6, then forbid ISPs to advertise IPv4-only connections as "Internet", then ban the selling of new IPv4-compatible devices.

(In a few years we're going to reach anyway the point when IPv6-only connections (mostly in Asia) outnumber IPv4-only devices (mostly in Africa, which sucks because they're the least able to afford an upgrade, but then being forced behind CGNAT sucks too).)

Ok, at least in Germany I noticed since I moved here that all residential routers were dual-stack. I even ended up disabling v6 because I wanted to run some things in my home network and I wasn't too sure about the firewall configuration.

Something that I find incredible, but have seen no one contradicting yet, is how when ISPs have started to roll residential IPv6 by default some years ago, they first had no firewall on IPv6 and/or later it was disabled by default (so only few % of users would enable it at best). (Not sure if the situation has changed ?)

Now, IPv6 (when properly implemented, which is another failure mode) comes with much better safety out of the box (like not being able to scan all the suffixes in a reasonable amount of time to find computers on the local network to target), but I'm still impressed that now we seemingly have hundreds of millions of personal computers "directly" connected to the Internet with at best only the OS firewall as protection (when one exists), and it hasn't resulted in major hacking issues ! (yet.)

The difference is a direct IPv6 conmected Windows 7-11 is actually prepared to be on the internet in a way that Windows 95 never was.

There never really was any such thing as a safe network, but it used to be acceptable to assume LAN traffic was safe. Now we know you might be on airport wifi or a large corporate network with compromised systems and the OS and systems software needs to handle that.

Right - and pre-Windows Vista, you would have to install IPv6 support yourself ?

I guess the hackpocalypse will have to wait for when low-end computers (like those in tvs, cameras, personal assistants, connected doorbells, home automation, refrigerators) - you know, "Internet of Shit" that you can't really expect to feature its own firewall (?) finally get upgraded to IPv6 ? (How does it look like today ?)

Germany is one of the better countries when it comes to IPv6 adoption, and even then it's only about ~55%

https://www.google.com/intl/en/ipv6/statistics.html