What is the rationale behind std::bind and std::thread always copying arguments?

Question

It\'s pretty well known that the default behaviour of std::bind and std::thread is that it will copy (or move) the arguments passed to it, and to use reference semantics we will

Answer 1

The most probable reason is simply that C++ uses value semantics by default pretty much everywhere. And using references could easily create issues concerning the lifetime of the referred to object.