I feel like I already explained it's not even part of the language itself, it's a library feature, you aren't given this feature without the rest of the hosted C++ standard library.

Which is fine if you write Windows desktop apps, but this is an array type, unlike a GUI widget, or an XML parser, it seems like I'd probably want an array type for this $1 per unit micro controller I'm writing firmware for. In Rust the nice array type works just fine, it's a proper first class type, it knows how big it is, mutable arrays coerce into a slice I can sort (only unstably, but hey, we're embedded firmware let's not get fancy), I can iterate over it properly... in C++ only the crappy C-style array is available unless I can butcher the std::array so that it works outside the hosted library. Ugh.