ISPs didn't use it in the early days, but it was used in corporate/organizational networks. The PIX was apparently marketed as a security appliance (heh) so that defined the user base to a large extent.
You can access the web over v4 with other kind of proxies besides NAT, for example application level HTTP proxies.
If you want working v4 for all the protocols, NAT is out by definition anyways.
You can access the web over v4 with other kind of proxies besides NAT, for example application level HTTP proxies. If you want working v4 for all the protocols, NAT is out by definition anyways.