Well, in the 90s, you would be able to get a /24 by just filling out some paperwork. How is it today, how easy and cheap can I get a /24 now? Is it two forms and an email?
The simple reason people have to start paying AWS for them is that it isn't easy or cheap for AWS to buy large ranges anymore. If it was just "fill out a form telling someone I need 4 million more IPs" then AWS would have some cheap junior technician doing that, but now they need to rake in money to cover the expenses to get IPs and customers that need v4 needs to pay for it.
You can check the rate of handing out v4 ips in 2012* and see that it was never going to be sustainable. The solution to the known-in-advance problem of ipv4 running out was not to .. not hand them out and just leave internet as it looked in Jan-2011 when IANA ran out of networks to hand out. So while it may be fun to state "I heard this long long ago", it just means others had better vision than you.
When we initially ran out of IPv4 addresses, the effects aren't immediately felt since there was an inertia.
But nowadays the effect is more than visible (especially in my region, Asia-Pacific), with more and more ISPs putting their customers behind a CGNAT. Let me write a parody of one of the classics:
First, they put cellular users behind CGNAT, which is fine because mobile phones don't host services.
Then, they came for residential users on cheaper plans, which is fine because they are not powerusers and so are unlikely to host services.
After that, they put all residential users behind a CGNAT.
...
It is actually what I experienced throughout the last decade in Southeast Asia. Are the ISPs here doing this because they are being cheapskates? No. It's because we are genuinely running out of IPv4 resources forcing people to share them. We did not have the luxury of Western ISPs who were assigned millions of addresses, and buying the addresses is a costly endeavor nowadays with /16 IPv4 block literally costing millions today.
And if you think CGNAT is good, think again: (quoting one of my previous comments)
[...] you can't really build a truly-P2P network nor self-host a service on Internet when everyone is behind CGNAT. At some point, as IPv4 resources get scarcer, only corporates will have the ability to host services on the Internet, and I don't think it is in their interests to host Tor nodes, for example...
