Ah yes, computing luminary Larry Tesler, what an idiot, working at Xerox PARC. Whoof.

Decades is an exaggeration. It was less than a decade after Digital started using Control-C as a process interrupt in their PDP-10 operating systems (1967) to when Mr Tesler devised his mapping to a copy operation (1974-1976) for Smalltalk-76, and only four years after C was born. CP/M is the much more likely source of widespread usage of control-C as an interrupt, and it was contemporaneous (1974) with Tesler’s mapping.