> If anything, NAT has saved millions of wildly insecure devices running unpatched old Windows versions from getting pwned the second they connect to the open internet.

You can have a stateful firewall that blocks non-established-connection packs and all your publicly addressable devices would not be reachable. NAT ≠ firewall (though they often glommed together on CPEs).

And NAT is also giving a false sense of security in some ways: "this device has an RFC 1918 address so is not reachable, and therefore safe". Yeah, except if another device already on the inside is / gets compromised. Perhaps if everything had a public address folks would be more circumspect.