C/C++ is used to build the fundation of pretty much everything you use every day. I don't think a fast moving standard would be a good thing.
In some ways, I'd like the C standard to move a bit faster, to keep up with things like multi-threading (although there's an argument to be had over whether that should be defined as part of the language or left to vendor-specific libraries).
Another problem is that the standard becomes irrelevant. This is a concern for HTML5, because a 'rapidly evolving' standard means that things can be added prematurely - but once something is in the standard, it can't be removed (easily). At some point, you run the risk of having more companies go the Microsoft route and just abandon the standard altogether, and either stick with an older version, or just fork it into their own new language.
This is specifically about the C programming language. Can we not conflate it with a different language entirely, at least in this comment thread?
They do try and stay reasonably consistent so for example Long Long moved from C to C++. And C99 has reduced some other incompatibilities by incorporating C++ features such as // comments and mixed declarations and code.
Many C++ compilers actually are C/C++ compilers that decide what language to compile depending on command line flags and/or file name extension.
int* foo = malloc(sizeof(int));
int* foo = (int*)malloc(sizeof(int));