That reads basically like "if you seem cooperative enough with our extra effort to check your identity, we'll probably let you through". That's just a very different country from "you need greenbacks to buy a ticket over the counter."
Similarly though admittedly more permissive, with Amtrak iirc it's like: you need a credit card and they probably won't check your ID. There were several more years after 9/11 before the "papers please" principle came for the trains and buses too.
If you walk onto the train with a ticket you printed, I don't think I've ever been asked for an ID. I might if I were picking up a ticket at the station.
You definitely need ID for hotels a lot of the time. Not sure the level where the regulations are put in place--probably varies--and Europe is probably more formal than the US in this regard. Was staying with a friend in Europe about a year ago and they had to take our passports to the police station to make us "official."
As I wrote elsewhere, I also had a challenge in the US a few years back but I expect that, had I been at my usual chain, there would have been a discussion with the manager followed by "I see nothing, I hear nothing."
https://en.wikipedia.org/wiki/Aircraft_hijacking cites two figures for the U.S. rate of hijacking attempts near its peak. The higher one is "Between 1968 and 1977, there were approximately 41 hijackings per year." meaning once per 9 days, an order of magnitude below yours. The other is once per 13.3 days over 1968-72. If both Wikipedia numbers are reliable then the peak must be somewhat higher than 1/9 in 73-77.
I already said ID is not security. How many 70s hijackers got away unidentified? How many would not have even tried if they also had to show ID? I can think of one case, "D. B. Cooper".
This conversation just doesn't seem promising. Your initial wildly-off claim got me worried I might misunderstand the world by that much (I remember the 70s, fuzzily). I wasted time checking it, wondering if the actual peak might be in a year not mentioned, trying to find the paper Wikipedia cited: it was a non-open-access paper with at least four links to check; one of them did show the first page, which at least gave the figure in question, if not the ultimate source.
Similarly though admittedly more permissive, with Amtrak iirc it's like: you need a credit card and they probably won't check your ID. There were several more years after 9/11 before the "papers please" principle came for the trains and buses too.
E.g. search turned up a claim Greyhound "employees are not allowed to sell a ticket without an official ID" https://travel.stackexchange.com/questions/140703/i-have-no-...