First off this is purely a technical question and NOT a political question so please let's not make it one.
Apparently (more like obviously) according to the news today the Chinese are stealing technical data from the F35 project so this brings me to a question that has been bugging me for years. Why can't this data be shared between necessary parties/facilities within a closed system similar to but COMPLETELY different and cut off from the World Wide network instead of being world wide accessible and protected only by fallible firewalls and passcodes? If hackers/bad actors could not physically access the system then there could be no hacking to protect from? Am I totally off-base here?
Again PLEASE no politics