The major reason is due to the height factors in runway modeling. The average height of Chinese is 5’6.7″, Japan – 5’7.4″, and Korea-5’9″. Compare that to Denmark,the average being 5’11.1″, Finland-5’10” or the US-5’10.5″. That’s not to say that there are not tall Asians, but once they reach the height requirements there is also body type/size requirements and facial structure.Another factor is that even in Asian markets, they search for models who are also of European or Latin look.There is no one rule depending on current trends. There is no organization that sets quotas or laws regarding equality. Its just about what is the look at the moment. There was a time when Cindy Crawford was not the typical type of model. There was also the explosion of the Brazilian model, which one of them, Gisele Bundchen is the highest paid model. There has been a more recent trend in Eastern European models.So it appears that the Asian look is not widely popular to see significant amounts of models with it on the runway.