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 don't think they got it "right" as much as they got it "right enough" - to the point where the effort to transition to a better set of tools would not be worth the benefit.
cf. Neal Stephenson's thesis about the reasons for "Innovation Starvation"