Devil’s advocate: compared to assembly, C is portable, but compared to a lot of high-level languages, C isn’t very portable.

Every “implementation defined” feature (https://en.wikipedia.org/wiki/Unspecified_behavior#Implement...) creates two different languages (examples are sizes of basic numeric types, signedness of the char type, and evaluation order of arguments)

Also, the standard library is so limited that, historically, you needed lots of stuff that wasn’t standardized between systems (https://en.wikipedia.org/wiki/GNU_Autotools: “It can be difficult to make a software program portable: the C compiler differs from system to system; certain library functions are missing on some systems; header files may have different names.”)

But yes, bringing up C on a system is a lot easier than doing the same for, to pick another extreme, Ada, but that’s because only half the job is done. Autotools does a bit of the rest, but still requires help from program writers.

Yeah, but isn't due to the language, rather to the amount of people that have spent money and resources to implement compilers for all those CPUs and OSs.

Original C was created after UNIX already existed, used for UNIX's first rewrite and until UNIX source code left Bell Labs, it only worked on PDP-11 computers.