The Xerox Alto was early 70's and that GUI OS was written in Pascal. I always thought Pascal was better designed and less bizarre than C. Null terminated strings were particularly a bad idea.
https://www.cs.virginia.edu/~evans/cs655/readings/bwk-on-pas...
One of the major problems, as I recall, was that Wirth's basic Pascal definition was very limited---the max 256 character strings, for example. So the makers of "production" Pascal compilers added extensions to do all of the things that you would want to do and unfortunately those extensions were all incompatible.
Here are two, RatC, Small-C.
Additionally what do you think GCC C is, in regards to K&R C and ANSI C?
Still, that was a much more powerful machine than the ones people wrote C for. And when the cheap segment of those "fridge computers" became powerful enough to run whatever you wanted to put on it, people started using small workstations. And when those workstations became powerful enough, we got PCs.
It's only when the PCs got powerful enough that we could start to ignore the compiler demands and go with whatever language fit us better. (The later reductions all were based on cross-compiling, so they don't matter here.)
Let not say that a 1961 system is more powerful than a PDP-11.
Several years later, a similar encounter with Mesa's evolution, Mesa/Cedar, gave birth to Oberon.
As for being ahead of its time, very much indeed.
Many people relate to Smalltalk and Interlisp-D, and are unaware of strong typed systems programming at Xerox, with a tooling that only decades cater came to be.
Mesa authors were quite adamant that in order to succeed, Mesa had to support comparable tooling to Smalltalk and Interlisp-D environments.