Question

Trade occurs only when nations expect to gain something

Answer 1

I'm not exactly sure what the exact question is, but true? They always expect, at least, to not lose too much? The Chinese government, for example, was forced at gunpoint to accept the trade of opium. The consequences of not doing so would have been the collapse of the entire Imperial system at the hands of the West. In short, it follows the same laws of desperate advantage-grabbing as all human civilization.