How to Prevent Hacking of the Computers of American Corporations and Governmental Entities

1) If the information is highly sensitive, don't put it on a computer connected to the Internet.

I read that Internet thefts by the Russian and Chinese of American technology represents the largest transfer of wealth in world history. I haven't been able to verify the statement. However, the aggregate theft is surely huge. Why do we leave it exposed?

2) Why are employees of American corporations and governmental entities issued computer terminals over which they could download a computer virus or other malicious code?

Why not issue each of them a "dumb terminal" (screen and keyboard) and a cable to the company's main computer. Then the company would not have to ask its employees to comply with proper computer security protocols, the company could control its own computer.