Honestly, I wonder why Pascal doesn't dominate, too. Safer than C while still just as powerful, "teaching language" (easy to learn) but used for serious software (as you note, Apple used it for system programming). FPC is amazingly feature rich.
When Apple ported their code from the Lisa to the Macintosh they had to rewrite a lot of Pascal code in C and assembly to make it fit into the ROM's. There was also an issue 100% standard Pascal was useless for writing micro computer programs because it couldn't do any IO outside the console and files. C on the other hand through pointers and inline assembly allowed you to directly monkey with the hardware.
Thing also forgotten how many early PC programs were written in assembly.
The Mac was programmed in Object Pascal and assembly. No C anywhere.
C compilers for the Mac came along later, and even Apple A/UX Unix System V with BSD extensions, and Gcc. A/UX ran pretty nicely in 8M on an SE/30 (512x342 mono CRT), with a MacOS 9 GUI emulator you could run xterms on.
Note, however, that he wrote this in 1981; these days, when someone speaks of Pascal, they usually speak of a dialect based on Turbo or Object Pascal, which appeared in 1983 at the earliest and address many of Kernighan's concerns.
tl;dr the Pascal of the 1970s was a lot rougher than the Pascal you probably know.
Especially the lack of separate compilation units was a weak point of the original Pascal, as also noted by Kernighan. This was fixed later in UCSD Pascal (1978) and of course by Wirth himself with Modula-2 (also 1978).
But that said, it's strange that Kernighan wrote the above article ("Why Pascal Is Not...") in 1981, i.e. three years after the introduction of UCSD Pascal and Modula-2.
Does anybody here know the background of that article? Why was Kernighan feeling the need to defend C against a 13-year old language which was already not in use anymore in its original form at the time the article was written? Was C under attack and risking to lose its popularity?
It should be noted that even when Kernighan wrote that, with the exception of the stylistic bits (e.g. where you put the semicolon), most of the issues he has didn't exist in the Pascal dialects that people used. His comments were about standard Pascal but few really confined themselves to standard Pascal - even the standard itself didn't do that, IIRC it explicitly mentions that implementations are going to extend it as that was an expectation at the time. In general Wirth's languages weren't meant to be taken as a gospel but as a base to expand from (even his own Oberon system slightly extends the language described by his Oberon language report).
The thing I saw with Pascal in the late 70's / early 80's was that in order to handle industrial use cases, each computer company invented its own dialect (I worked on one at Burroughs).
That was one of the problems Ada addressed. But its initial problem was the cost of compilation and builds on the hardware of the time. That got sorted out by the end of the 80's, but then other factors like contractors not wanting their customer telling them how to do their work came into play. Sort of a confusion of requirements and implementation methods.
