Indeed. The 'hop' argument is only "true" with IPv6-over-IPv4 tunneling, where the real hops are concealed. Of course, the effect is actually the opposite: you have less efficient routing from source to destination because you have to go through tunnel PoPs, plus processing overhead.

Regarding security, it is still possible to provide the same "security" as NATed private addresses on the network gateway level. However, with some carriers it was (still is?) possible for a long time to communicate with other private IPs without any firewalling, making the argument moot. This also had the bonus feature of bypassing traffic accouning, allowing to have free unlimited traffic via a VPN between two customers.