In the 70's and 80's C and Unix were incredible tools that were so close to useless that they could run on cheap computers, and so unappreciated that you could get them with a personal budget or for free.
They both were extremely important on the popularization of computers and on unlocking the huge amount of value they provide today. But not due to any quality that we value today.
As soon as a viable alternative pops up for nix which has all the advantages of current incarnations - of which 'open' and 'free' are but two of the more important ones - they'll take over the world. Until such a time we'll keep on using our nix-hammers just like carpenters have been using their hammers (nowadays often driven by electricity or air) because they work well enough for the intended purpose, the occasional blue thumb notwithstanding.
We hacked most of the advantages of anything newer back into them, in a haphazard way, and kept them because as a sibling pointed out, nowadays they are open. And openness is a very important feature. (It's just not why they were adopted, people cared so little about openness that Unix was born open and mostly closed up later.)
They both were extremely important on the popularization of computers and on unlocking the huge amount of value they provide today. But not due to any quality that we value today.