My university has a public IP for every computer, but you could still only connect to the servers, not random computers, from the outside. Because they had a firewall.
NAT/port forwarding, for all their faults make it rather difficult to write rules allowing traffic to a machine you didn't intend to expose to the world.
This is not in any way a benefit of NAT.
Just because NAT accidentally achieves some good outcomes doesn't in any way imply that said good outcomes are somehow exclusive to NAT.
Obviously, those average people have a suitable firewall provided by default on their routers.