What's the significant difference between having users, and having a chain of users, in purpose, philosophy and reality?

if we simplify it to being an OS (systems) vs a gui (applications) programs, we can see their purpose, philosophy, and reality. The OS' purpose is to run other programs, and thus that interface, Elf, is full of technical implementation details fitting the philosophy of a OS that allows multiple processes to run, and reality - Linux (OS) does not compete with Airbnb (application).

Contrast this to a GUI program a user interacts with. Its purpose is dependant on its relationship to the user. The philosophy is that the user could click on anything on the screen at any time, so the program had better be ready! The reality is that users live in their own world, free from all concerns of the silicon world, except one - power. They may perceive memory pressure in the form of slowness, but they don't feel it the way the operating system does.

This appears both incomprehensible and wrong, but let me check if I understood.

Systems:

- Lacks a GUI.

- There are technical details.

- Doesn't compete with applications.

- Memory pressure is an issue.

Applications:

- Has a GUI.

- Need to be responsive.

- Power usage is important.

- Memory pressure results in slowness.

I don't think we got any closer to a useful answer.

It can't have been that incomprehensible if you got that much out of it, but I mean if you're going to call me wrong, what's your take?

I don't think there's a significant difference and I don't see the importance of making the distinction.

UX?