Well, I think it's necessary to draw a distinction between those who genuinely love food, and those who run restaurants due to economic necessity/lack of other skills. A dedicated chef, who's willing to research & practice, can learn to cook any cuisine well. However, if you don't have a passion for your job, you're not likely to cook well anything but that which is most familiar to you- the food of your own culture.
The "Chinese people making terrible Japanese food" people are complaining about are probably very cheap, hole-in-the-wall places that decided to be Japanese out of a perception of more profit and less competition (as >>4 noted). Part of the poor quality would be the prices. Japanese food demands very high quality ingredients, and you just aren't going to get those in four-dollar bento boxes and one-dollar sushi.
In little family places like that, who knows if the chef even read a cookbook? Can't blame him. For the price of buying one he could feed his family for a week. Besides, you wouldn't think it would take much skill to cook a breaded porkchop- unless you're already knowledgeable about Japanese food.
Lesson: Stick to what you know, unless you're willing to learn.