Running outdated software is bad thing. Debian's aptitude resolves dependencies and installs them automatically. There is also nothing stopping you from installing older libraries if needed. If you really want to run 8 year old software on Linux, you can keep your 8 year old operating system .iso you downloaded and run it from that.
But, with regard to Windows ... maybe it's less about proper package management and more about componentizing Windows a bit better. Even without considering third party software, Windows itself could benefit from this.
Here's an example: In Windows Vista, they introduced DreamScene, which allows you to set a video file as your background. It's a useless feature to me, but hey, someone else may want to install it. I might even want to install it temporarily just to use it. To my knowledge this feature is unavailable in Windows 7. I mention this because it's something like an optional "package" that you can install after your Windows install is complete.
Now, go to Programs and Features, and then you'll see Turn Windows Features On and Off. So here, it looks like they have the beginnings of a repository. You can enable and disable things here. But to me, it would make sense for this to go out to a Windows repository online, look for available Windows packages, like the aforementioned DreamScene, find out the latest version, and let me install and remove from there. Also, maybe let me add certified Windows packages from a CD for those in extra secure or disconnected situations.
So why can't individual features be updated and upgraded when ready, independently of the Windows version, instead of forcing it upon users to jump to a next major Windows revision? I understand the necessity for such things with regard to basic OS architecture - for example, DirectX 10 needs the Windows Vista kernel. So it may be easier to say certain packages require a specific Windows version instead of the hundreds, if not thousands of files that it depends on. But there are numerous smaller features that I'd love it if I could install on demand.
We all know why this won't happen, which is because Microsoft wants to force things on the user. Microsoft wants to force Metro on you, to collect app revenue like Apple does. Microsoft wants you to upgrade to a new OS every two years. Microsoft cares about its relationship with antivirus vendors more than your security, etc.