"Keep in mind that back then"
Keep in mind IBM back then was one of the largest international companies, unlike Bell or whatever, which had a far narrower US focus. IBM was much more used to work with international customers, and its designers were probably much more aware of the need of avoiding input issues.
Kernigan & C. were exactly a "bunch of engineers" working in a lab, uni or Bell changes little - what else? Do you believe they are "gods", and as such they can't make mistakes? Unix and C are full of bad design decisions that could have been easily avoided looking beyond the nose, and knowing the world better. Actually, they are roadblocks to better systems, as too many people have been brainwashed into thinking they are perfect and don't need changes to cope with a far different world compared to 1969.
Remapping keys is not a solution, because unlike 1969 applications are interactive and need to manipulate and display a lot of strings, so you have to type them as well, even if you use a language like C that still stubbornly tries to avoid the idea of a "string" - which is not an array of bytes, its semantic is far more complex - again, something that works only maybe in ASCII7.