Rust's &str is basically identical to C++'s string_view, for what it's worth. I still don't understand your point about how string_view is inconsistent. The only reason &str is so much easier to use than string_view is because Rust supports borrow checking, making it safe to use, whereas C++ does not.
What I meant about "inconsistency" is that there are std::string_view constructors that accept raw pointers to indicate the range, and others that accept iterators. It's a mix of old (C) & new (C++) data structures, with neither indicating the ownership or longevity of the underlying object.
This is somewhat typical of where C++ is at nowadays - layering new functionality on top of old that wasn't designed to accommodate it. In an ideal world the language and libraries would be refactored and rationalized, but of course backwards compatibility precludes that. This is the fate of old languages - stay unchanged and become obsolete, or keep layering on new functionality and become messy and inconsistent.
