Taking a contrarian view to everyone else in this thread, I don't think Unix rocketed C to stardom - Turbo C did. Turbo Pascal was very very popular for PC programming and was eventually supplanted by Turbo C and Turbo C++. Without Turbo C, I think C would have probably become just another niche language used on a niche OS, Unix.
And in line with what you say in another comment, commercial OSes -- including VMS -- were very powerful and much more popular than Unix. In 1982, a single VAX 11/780 running VMS with 4 and 8 MB of RAM could support 10s of programmers editing, compiling, debugging, and testing code. VMS was also a real-time operating system that we used in production to control/monitor/perform-I/O hardware devices handling LANDSAT image data. And Unix is still trying to figure out async I/O ... (Most of my career has been spent on Unix, but I appreciate other operating systems I've worked on as well.)
Lisp has the code-data duality (everything is a list) going for it and C has everything is pointer to a block of memory and that's it. That block can be a device register, data structure, array of sth. or just about anything you can imagine. This idea enables you some kind of proto-polymorphism without the verbosity and chains of higher level languages (at the cost of safety of course). That is the beauty of C and unlike Lisp it is also lot closer to the metal, which helped a lot with performance.
I think it's normal to be jaded when something objectively superior is being replaced with something simpler. But that doesn't mean the simpler thing is without merit. The world has more dimensions, the technical aspect is just one of it.
C is not significantly different from Algol or Pascal. The difference between C and Algol is a lot smaller than between either of those and Lisp or ML.
What's missing in some Algol-like languages compared to C is the loose pointer arithmetic, and possibly type punning via pointer conversions. Those features allow C programmers to do things like write their own memory allocator, which is incredibly useful in embedded systems. A C project can produce a self-contained image that boots on bare metal, with minimum assembly language. Or on almost bare metal, where there is a boot loader program that provides no services to the C program other than jumping to its entry point and maybe some console printing routines or something.
As an embedded developer in previous life, I can assure you C is not special because it can run on bare metal. Many other languages can too.