The problem isn't bounds-checking, the problem is that most of the _s() functions that deal with bounds-checking already have pre-C11 equivalents that check boundaries.

I also disagree with some of the interface choices, for example when strlcpy() fails it tells you how many characters you needed, not simply "error" as in strcpy_s. Also the use case for memcpy_s() is extremely limited. It just seems like the _s() functions were rushed and stuck in there without regard for what makes sense.