Japan is another Asian country with no comparable tradition of post-dinner sweets. People there snack on a wide variety of cookies, crackers, other treats, but in general the Japanese have much less of a sweet tooth than Americans do. (I've yet to come across a Japanese who could, say, eat an entire American-sized Snickers bar.) Although every new generation of young people in Japan seems to have a higher tolerance for rich, European- or American-style sweets, this is still a recent phenomenon. Traditional Japanese candy (wagashi), with few exceptions, doesn’t even approach the sugar content of even old-fashioned (let alone modern) American sweet treats such as ice cream, cola, cakes, and pies, etc. Even Japanese versions of imported confections register lower on the sweet-o-meter. (Ever tried Japanese chocolate? Most of it tastes like soft wax with some chocolate mixed in.)
The ultimate reason could be that until recently in historical terms, the Japanese diet was high in carbs (rice) and vegetables but low in protein—fish and meat were considered the ultimate gastronomic treat, not high-sugar-content desserts. This also explains the postwar explosion in sushi shops: fish so fresh that you can eat it raw was, before that, a luxury affordable only the very well-to-do. So, after industrialization, people began eating more sushi and more beef. (But still not at American levels. Until Japan began importing more beef in the last 10-15 years, it was much more expensive than in America and at many households was—and still is—a special treat reserved for company or other special occasions.) It could be that our sweet-tooth gene kicks in only after long-term protein intake reaches a certain level. Historically, perhaps Europeans, with supplies of beef and other animal protein more ample than what was generally available to Asians, could then move on to the next step: sugar.