My impression is that desktop software is/was largely written in C/C++/C#/Objective C/Objective C++ because those are the languages to which the Operating Syste

My impression is that desktop software is/was largely written in C/C++/C#/Objective C/Objective C++ because those are the languages to which the Operating Systems of today expose their APIs. For example Win32 = C/C++, Cocoa = Objective C, Metro = C# (or I guess anything compiled to the Common Intermediate Language (CIL)???). Now that said, most languages provide a bridging layer that allows them to call out to those "native" APIs. These are used to enable API ?wrappers?, however due to these being provided by third parties (I believe) there has been a tendency to gravitate toward the "blessed" language of the OS vendor. One of the big advantages of Java (to me at least) was that it provided a platform independent windowing capability inbuilt within the JDK that has been maintained by Sun/Oracle/(and Apple) as new operating system revisions were released. Note, for example, that C/C++/Objective-C/Objective-C++ programs aren't/weren't allowed in the Mac App Store (I'm not sure if this is still the case...). (Personally I ported a Java App to Objective C++ due to this.) But generally I agree with your point that this isn't the only reason why C was so pervasively used. However, you also need to consider that a large number of programming environments and tools were specifically developed to aid C/C++ programmers, e.g. Borland C++, Visual C++, Code Warrior, XCode. It's also worth remembering that the GNU C Compiler and Debugger were import contributions to free software back in the day. But also consider distribution of compilers etc. I think it is pretty fair to say that a lot of programmers learnt to program using Borland Pascal/C++ because at that point the Internet was not as accessible as today and copies of these could be "obtained". The advent of Internet has not only allowed the distribution of compilers and environments for other programming languages, it has also meant that the languages used for backend systems, i.e. web servers and web applications, is irrelevant to the user's web browser. Anecdotally, for safety-critical system software an issue with some languages other than C is that they have not been suitable for real-time systems. I don't know much about this other than that exception handling and also garbage collection can cause issues due to their non-determinism. I fear that you'll think that the above is a bit too much like saying "all software is 'C' because it needs to do system/library calls", however I think it's probably fairer to say "all software is 'C' because many people have really, really liked it" and "better the devil you know".