The difference is in that every single one of those other operating systems, applications just have network access. By default. No capability needed. This would not be the case in an OS centered around capabilities.
Multi-platform software develops integration with local OS APIs all the time.
Like I said, your thinking is way too black and white. Your inability to see a different world doesn’t make one impossible to exist. What is even the point of thinking this way? Your entire mindset boils down to “nothing can ever be better”.