Why is the engine so bare bones?

So don’t get me wrong, I absolutely love UE4. It’s a real dream to work with and I’m so happy with what you can do with it. That said, I’m curious why the engine is so bare bones in the sense of certain functionality that every game would be able to take advantage of such as a working and fully implemented menu system (with graphics and audio settings, button remapping etc.) or a save system, or proper game list and chat etc. for multiplayer games.

I understand that each game is going to want to customize these features to fit their game, but it would be nice to have a base framework to work off of rather than having to make everything from scratch.

Is it because of the market place or are these just features that will be added in time?