The description is over-simplified in that it ignores the prevalence of pirates and brigands along the routes, especially at its borders. Take a look at any of the caravansaries along the silk road for a clue as to the safety of traders who joined caravans for their mutual protection.

As far as China is concerned, to the best of my knowledge, they have not fought a major war since the Korean conflict over 70 years ago. That's not because they are incapable of winning a conflict, but because fighting an expensive and disruptive war is counter to their interests. It is my belief that China would have as much military damage from the US if it took Taiwan as the US would suffer from China if it took Greenland. Neither country can afford to directly target the other militarily. The dangers to both would be economic in the form of sanctions from the target country's allies.

In the meantime, China is OK with Taiwan being an autonomous portion of their country as the amount of profitable trade between the two is huge. The only thing which would precipitate an attack is if Taiwan was about to become militarily strong enough to deny China the ability to easily invade in the future. Similarly, as long as trade is profitable to China, there is no reason for China to invade any of their neighbors.

Jeff