I'd guess this is more like "space reserved for system purposes" than OS size alone. You need space to upgrade OS components, probably space for the hibernate-l

I'd guess this is more like "space reserved for system purposes" than OS size alone. You need space to upgrade OS components, probably space for the hibernate-like feature of consoles and a bunch of other stuff I don't know about. They also can't easily increase the amount of storage for the system, but they can decrease it in the future. So they might include a bit of buffer they don't use yet.