Restaurants don't have a high barrier to entry, but they are low margin businesses with high risk and low quality of life. You need a certain population density of restaurant-going population (younger people usually) to sustain a variety of restaurants.
Population density of Asia isn't comparable to most of the US, plus the US has stricter food regulations, plus people in the US have better options than working at a restaurant, so the labor is costlier, hence the food is costlier, hence eating out as often as Asia might not be possible.
My original point, however, was to dispute the claim that chain restaurants make it harder for others to compete. I can't think of a single thing chain restaurants do or can do to prevent competition, except maybe with liquor licenses, but there's no one stopping small Asian style shops from opening up other than higher costs of doing business in the US and insufficient demand.
I currently go to a food truck once a week or so because it provides a hot lunch, of reliably decent quality, both faster and cheaper than nearby sandwich places. Other food trucks I've seen at other places and other times of my life have followed similar patterns, and if I've gone to them it's for similar reasons.