Except tabs in makefiles only require ones to acknowledge 'makefiles use tabs and here are the rules'. It's otherwise only something for pedants to obsess over.
IPV4 address contention has a bit more real-world impact.
No one and I mean NO ONE had any clue how widely deployed IPv4 would end up being. It went literally beyond everyone's wildest expectations who was alive at the time of its inception.
I don't think anything I wrote disagrees. As someone who started implementing IP networks just a couple of years after RFC791 was published, I'd say that was completely correct. But more than 40 years later, the fact that it has gone beyond everyone's wildest expectations means some of those early design decisions are starting to bite. Unlike tabs in makefiles, which is just something certain types of people like to complain about.
IPV4 address contention has a bit more real-world impact.