Well move semantics were only introduced in C++11. So until C++11 is supported natively everywhere you can't build something like: std::map<std::string, int>

Well move semantics were only introduced in C++11. So until C++11 is supported natively everywhere you can't build something like: std::map<std::string, int> without paying for a extra copy of the string on insertion. How many years since C++ has existed before they finally allowed for a single copy? Everything is relative. You might never have had a need to worry about that double copy, but there are other people who have.