There are basically two ways to look at the fact that we're still using many of the same command line tools today that originated on UNIX of around half a century ago:

1) Serious stagnation
2) Ken and Dennis and the rest of the gang in the Bell Labs MH1127 lab, etc. got it right

L

@lauren I will say that the GNU userland brings enormous improvements IMO, but otherwise #2 all the way. The GNU userland basically layers a myriad of quality-of-life improvements over the same fundamental toolkit, and the toolkit itself was sound.
@marsroverdriver Given the tug-of-war over UNIX that occurred way back when, I migrated my systems from UNIX to Linux as the latter became more full-featured. In general I've found the GNU userland to be a significant improvement, but I would not claim that it moved things in a direction that would be beneficial for most non-techie use. And there's an undercurrent of you-know-who's philosophy in there that sometimes makes things overly complex.

@lauren @marsroverdriver as for your question in the original post, I think both can be true.

Also, for a long time there was no desire to make things actually better, and with the era of object oriented design, people were very confused about what was actually better for the user; hence Powershell.

These days, people still generally misunderstand what makes Unix tools good, but at least colour is a thing now (if only terminfo was actually good so people wouldn't hardcode escape sequences, but I guess one can't ask for everything).