K&R was published in 1978. So at best this story and timeline are incomplete.
More illuminating would be an account of why C beat these other languages in the marketplace in the 80s, despite its disadvantages in safety.
Had Bell Labs been allowed to sell UNIX at the same price as other companies were selling theirs, and C would never have taken off.
Burroughs, developed in 1961 in a memory safe systems programming language is still sold by Unisys as ClearPath MCP.
Same applies to the IBM mainframes.
The surviving systems from the 60-70's where C only plays a guest role at most.
Check language support across Small-C, Turbo C, Quick C, Aztech C, Metrowerks C and many others from those days.
Likewise it was possible to do the same across Pascal compilers that implemented variants of ISO Extended Pascal/UCSD Pascal, Modula-2 and a couple of other high level languages.
The whole point is that contrary to its sales prospect, not only does C also require to write Assembly, it doesn't have any language support for modern hardware CPU/GPUs, just like any other high level language, requiring extensions to the standard, not necessarly portable across implementations.