Ask HN: Why aren't there more centralized app repo's for Win/osx?

While I still am a huge fan of Linux and would love to go back to Linux, I've been using OS-X primarily for work. The one thing which greatly saddens me and makes me worry for the future is the lack of an open and centralized place (controlled by the user) to manage, install, find, update, and delete apps just like Linux has with pacman (Arch) or apt-get (Debian).

OS-X has the App store, but that's Apple controlled and limited.

Windows has ... ? I haven't been in windows lately so I don't know what it is. But at least windows has the Add/Remove programs panel!

So, why aren't there any real public tools such as apt/pac/yum (whatever) for Mac/Windows?

It seems like a single central point of search and control would make life a lot simpler (with the possible addition of certain UI elements, ect ect...).

Is there even anything like that around?