Tell me how you would ship a device for $20 that will support an arbitrary number of IP devices behind the firewall on virtually any ISP scenario out of the box with zero or minimal installation?
NAT itself doesn't create security, but it brings a standard use case that is easy to secure.
As far as security goes, firewalls don't require it. Not only that, but I share the admittedly minority opinion that firewalls are a crutch for bad system security and that we should be working to fix that problem. A system that requires a firewall to be secure is broken.
Tell me how you would ship a device for $20 that will support an arbitrary number of IP devices behind the firewall on virtually any ISP scenario out of the box with zero or minimal installation?
NAT itself doesn't create security, but it brings a standard use case that is easy to secure.