Re: "We have now run out of IPv4 addresses"
The problem is it was 1996 and "the Internet" was still a small "nerdy" network with very few commercial companies and almost no "consumer" users. So they believed they could design a system addressing (pun intended) some of the issues of IPv4, and switch the "hole "Internet" quickly.
It never happened - in the same years the internet took off quickly with the old design, and then switching became a nightmare. And IPv6 too got old issues arose even before being really used - as it was designed for a different era.