I think the issue with string_view is less laziness and more recency: most libraries still need to support C++ versions prior to C++17. Rust had the advantage that slices were there from day one.
I don't think it's just recency either, it's just incredibly easy to shoot yourself into the foot with string_view when the language has no way of checking that the pointed to memory is actually valid. People moved to smart pointers for good reasons and string_view just undoes all of that.
While using C++, adding something like gsl to the toolbox is worth gold, and also enabling bounds checking even in release (really, most of the time it hardly matters to the application users).