Note, the CIDR RFC didn't come out until Sep 1993. Thus even brand new network equipment in the mid 1990's were still very classful. And even then, knowledge of how to properly use /etc/netmasks in SunOS v4.x (or the equivalent if some other network stack even had one) was very scarce.

In the mid 90's, SMBs connecting to the Internet would have very typically obtained a /24 from their ISP, and had direct connection online, no firewalls, barely any proxy servers (although that was popular for some mid sized customers that would have needed multiple /24s or even a /16 to get all their workstations online).

It wasn't until the company Network Translation, with the PIX came about that anybody even considered doing private IP address in general as a firewall strategy with NAT translation using private IPs. And then it took years and years to become popular. Long bought by Cisco at that point.

I don't think Cisco IOS even had NAT until something like 10.2, when it was a premium license package.

I got a provider independent /24 block back in the 90's, when I was barely out of high school. I'm still using it to this day!

I remember those early days. No firewalls. No proxies. I had that /24 on my home network, totally unfiltered. Kinda nuts thinking about it today.