You can't compare US and China with respect to Tarvel - different model/markets:
First of all, the Chinese travel market is extremely fragmented. Unlike the US, which is dominated by a few big OTAs, China has over 25000 travel agencies, and the number is still growing .The fragmented market gives Qunar numerous clients and a huge bargaining power. Secondly, Chinese travelers are very price sensitive. Ctrip, the largest OTA known for its good service and resources, had to join the price war in 2012 as they lost market shares rapidly to the lower-end travel agencies. The price sensitively prevents travelers from sticking to any OTAs, making them go to Qunar to search for the lowest price. Thirdly, Qunar is owned and backed by Baidu, China's dominating search engine. Baidu gives query traffic to Qunar, and traffic is king to any search engine or OTA.