A pseudo-filesystem is not high-overhead, unless you believe symlinks and pointers are high-overhead.
>First of all, you just called PATH straight-forward. Try explaining PATH to the average desktop or mobile OS user, and then try explaining why this is better than the App Store or drag-installs.
Here's the thing: an 'average user' doesn't care about 'a ton of files splatted over the disk' either. How many Windows users bother even looking in the Windows directory or Program Files directory? The 'a ton of files splatted over the disk' issue is only an issue for power users, who like to feel in complete control of their system.
As for App Stores, they're just like a traditional package manager but with a simpler UI and the option to buy software before downloading it. If you're familiar with Ubuntu, compare Synaptic with the Ubuntu Software Centre? See a difference beyond the cosmetic layer? Now compare the Ubuntu Software Centre with the Apple App Store, can you see a difference beyond the cosmetic layer?
I've got a strong feeling of déjà-vu discussing this, are you a Haiku-OS.org forum member?