Are you thinking hack proof software? Are you thinking of shutting off the physical connection to bad actor nations?
First thing to understand. Nobody owns or operates the Internet. The Internet is a collection of interconnected networks all using Internet Protocol. There isn’t a single connection between the USA and another country, there are 1000s of ways in/out of the USA to other countries connected via the Internet. So if your theory is we could close off the connection to another country, say Russia, that would be impossible. Example, a company like Microsoft (and 1000s of other “western” companies) have their own global networks (that isn’t the Internet) that connects to the Internet in numerous different countries. All a hacker needs to do is hack into one of the locations and they can sneak into any other entity connected to the Internet anywhere.
What’s to prevent a North Korean or Chinese or Russian hacker from coming to the USA and setting up shop?Hack proof software is lofty goal, but so is an accident proof automobile. Software is written by humans. Those humans aren’t perfect. Those humans are under schedule pressure by their employers, the developers and testers aren’t allowed the time to make it perfect. There will always be security holes that can be exploited. It’s a game of whack a mole. Soon as the good guys whack one mole, three more pop up.
Another thing to understand is that most hackers don’t “break in”. They trick unaware/uneducated Internet users into downloading and installing some piece of software that opens a door for them to get through. Making a hack proof Internet would mean that all its users have a clue, good luck with that.