Never attribute to malice that which is adequately explained by stupidity.

All of this stuff is 50 years old and there's no way the people who put these systems in place could have ever predicted the Internet as it is today. Famously in 1973, there was a "map of the ARPA network", that's how few machines were "online" at the time.

It's really only in the past 10 years or so that security via TLS has been widely adopted by websites, and it's been over 20 years since IPv6 was announced and still is not entirely supported everywhere. There is so much inertia with the underlying infrastructure of the internet, even if there is a serious issue (like DNS cache poisoning ), systems will not be reworked and replaced, but hacks will be added to fix the issue of the day.