Storage space used by System software

Jul 22, 2018
I looked at the Moto G6 as well as the Nokia 6.1 at our local Best Buy store. One thing which I noticed is that the Moto G6 uses about 6.7 GB for storage for the category "System" whereas the Nokia 6.1 uses close to 11 GB. If the Android in Nokia 6.1 is a purer version of the Android Oreo, why does it take more storage space? Any explanation?
You would have to ask someone at Nokia. While the original Android version of any build for it would be the same, the phone manufacturers can alter it, add other things to it, etc.