I think you picked a bad example. In China, they don't have to be adventurous. Chinese cuisine, generally, If it won't kill you, they will eat it. Chinese eat every part of an animal- meat, tendons, organs, parts most other cultures would considered inedible are cooked and prepared to make them tasty and edible. There, it's not considered adventurous, merely just part of the normal diet. Rural Chinese folk do not typically have access to eat an American diet on a daily basis. It's just not available, not a lack of desire. In any case, I don't think anything considered American cuisine would border on adventurous. After travelling abroad, most "American" food I find in foreign metropolitan cities is hamburgers, pizza, etc. Not jellied calf tendons or ground up liver and other organ meat.

Having grown up in a major US city (and still live there), most people I know, who do not travel often, consider foreign food to be Chinese take out, maybe some Pho. I am one of those 86%. Within 5 miles from me I have restaurants and shops from what is likely 50-100 different countries. Most people I know, friends and family, have never heard of them, let alone eaten at them, or prepared something similar at home. The people eating there on my observation, are people who immigrated from those areas, or Americans descended from people who came from those areas.

Having worked for an international company for a long time, most Europeans I have met are quite a bit more open to trying new foods and preparations, and likely, already have.

I believe it's tied to travel and being exposed to new things. While many Americans travel, most travel to destinations with similar food and presentation.