[derefr]

> NAT only exists to workaround IPv4 address exhaustion.

Untrue; people were using NATs long before they were concerned with running out of IPv4 addresses. I think it was a bit of paranoia combined with lack of trust in firewalls: corporate sysadmins just didn't want their internal networks to have routable addresses.

This seems to have been mostly calmed by the explosion of "cloud" IaaS offerings, which need publically-routable addresses to do much of anything.