Who, except for people too young to know better, saw value in C but not in Algol? The Bell Labs folks obviously thought enough of Algol such that C is a descendant in the family of Algol-like languages. Algol was widely used in Europe whereas in the U.S. we made do with Fortran, Cobol, and, I think to a lesser extent, PL/I, although the latter had many Algol-like features at the time. (And Fortran evolved to have many of those features; I suppose Cobol also, but I'm not familiar with its post-1981 history.)

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.)