Why can't you completely disable quick resume?

because it's a basic part of the operating system that cannot just be disabled without potential catastrophic consequences. It's the same reason why you can't delete your achievements. You don't want to remove things from a giant database because he couldn't have cascade failures that wipe everything.

Disabling quick resume is currently being looked into according to Phil Spencer, whether or not it can be done is still up in the air, and the next time there is news, there will be some kind of public announcement, likely as part of a major system update

Disabling quick resume is being explored, but there is no ETA on when it will happen or even if it can. Quick resume is baked into the hardware at very low level and may not be able to be disabled.

I can understand exactly how you feel. I be loading into Apex Legends and get disconnected, It would nice if quick resume was toggle able

Quick resume is not something that can be disabled at this time. You need to go out to the dashboard, hit the start button on the game, and go to quit to ensure it does not enter quick resume

Games that support quick resume automatically add when you start them. There’s no way to disable quick resume

I just delete it after I manually quit the game every time.