I am surprised he would find any mac directly connected to the internet post 2003-2004. Unless you are connecting with 3g/4g directly, you are always behind at least a nat.
For IPv4, at least, if you connect via 3/4g you're going to be behind CGNAT. Far as I'm aware, there are no mobile operators left that don't NAT IPv4 traffic. IPv6 is different, of course, but I'm uncertain how well 14yo malware is going to deal with IPv6.
Plus good luck scanning the ipv6 address space.
Massscan upgrade needed.
IPv6 is 20 years old
But 14y ago you would be lucky to even have an ISP that would allow you to send an IPv6 packet.
My university connects everyone one the wifi directly to the internet... as an example.