> There is more to shells and text interfaces than working within constraints set 50 years ago.

Of course.

With some minor changes, you could make the same argument many, many technologies we use every day, from IPv4 to SQL to C.

Then there is the old saw -- likely apocryphal -- about how railroads are the width they are because they evolved from standards around Roman roads. Even if it is a fairy tale, the moral of that story strikes true: existing tools are built on top of old ones, because it was better to have a standard then even if we may know better now.