I think the language committee should provide a spec where required (OS filesystem, mutex, etc). And when it is not required they should simply provide a plain bog standard library.

There is absolutely no reason for std::deque to be a specification. The committee should either ship a committee library for std::deque or they should leave it to the community. They can provide a battery or they can not. Providing a spec for a battery that is both over and under specified is the absolute worst possible choice.