No it doesn't. Download ATM free or OS Monitor and watch all the processes out there floating around. Sure, they are not all foreground processes, but they are out there, they consume some space in memory. Some are services, some are processes.
Who cares if apps are taking up memory if the OS doesn't need it and they're not using CPU clock cycles. That's why everyone has it wrong. They think just because an app is sitting in memory using up RAM, that it's hurting the phone. If Android needs more RAM it'll start killing processes. If it doesn't, who cares if there's a bunch of apps sitting out there.
Hypothetical Example:
Phone has 10MB of RAM.
The user is using App A which is taking up 5MB of RAM
App B is sitting in memory taking up 3MB of RAM
There is 2MB left over.
Why kill App B? It's not hurting anything. App A doesn't need that RAM. The OS doesn't need it, if it did, it would kill it.
Now let's say the user opens App C, and it needs 3MB of space, but there is only 2MB free. Android will kill App B to make space.
This is an extremely over-simplified example. The point is, this is not windows, it doesn't matter if there is a bunch of unused apps and processes and services running as long as there is enough memory for everything. If there isn't, Android will free up space.
Everyone seems to be concerned when they see a bunch of processes running unused. Who cares!?!!?! There can be hundreds, as long as there is still free memory and they're not using up clock cycles, it won't affect the performance of the phone. If a background service DOES affect the performance of the phone, it's the crappy app's fault, not Android. Uninstall that app or check into it's settings to see why it keeps using up CPU resources.
I write embedded software for a living. It's completely different from Windows. If you see Windows constantly sitting at 95% RAM usage and 95% CPU usage, you would freak out and your PC would be barely useable. But this is typical for an embedded application. If an embedded application always has free resources, then the manufacturer picked out the wrong hardware. They could have saved money by going with less RAM and a less powerful CPU.