Is there some technical feature of C or C++ that makes those languages good for writing OSes, or that made OSes written in those languages overwhelmingly successful? You might argue that the simplicity of a C compiler made Unix successful because it helped with portability, but C is by no means unique in this regard -- a Lisp compiler can be equally simple, and can be used to bootstrap a more sophisticated compiler. Really, Unix won because the only real competition Unix vendors faced in the minicomputer and workstation market came from other Unix vendors; C was riding on the coattails of Unix. One would be hard-pressed to argue that Windows won because C++ is a great language, especially considering how Windows was plagued with bugs and security problems during its rise to prominence in the 90s (many of which resulted from bad pointer mechanics, which is what happens when you use a language that requires you to juggle pointers).

I'm not arguing that. I'm not even saying I know precisely why C or C/C++ is good. I'm just saying, when every major OS is written in it, can you really dismiss it so easily?