The reason is English proficiency: along the classical tourist route in Yunnan, from Kunming to Dali to Lijiang to Shangri La, foreigners find a network of hotels and restaurants and cafes where English is spoken or at least is on the menu. But this isn't the case in Sichuan; for example, out of more than 90 hotels in Jiuzhaigou, only at two of them - the only two five-star hotels - can anyone speak communicable English.
These difficulties also force most foreigners to travel in organized groups in China, even though foreigners prefer to travel independently.
Problem is that independent travel is frustrating in China partly because of the language barrier, and partly because many destinations or attractions in China are set up to cater for group travel.
This is because Chinese tourists - who account for the vast majority of tourists within China - mostly travel in groups on short trips. Foreigners travel differently, and they come from afar, so they would spend at least two weeks to justify the hassle and cost of long flights.
But the infrastructure for independent travelers is inadequate in some far-off out-of-cities destinations, such as the outdoor attractions and the ethnic villages of western China, which is the region that's most exotic from a tourism viewpoint. For example, I was in Kanas national park in Xinjiang the other week, and I couldn't find buses from Bu'erjin, the nearest county, to Kanas. I had to resort to taking a taxi, which was expensive given the distance and the drivers' unscrupulousness in prizing a high price from tourists who don't have another choice.
Now the chief of Altai tourism, in charge of Kanas, is meticulous in his job. When I went to talk to him, he rapped out statistics and explained the details of the management plan without consulting any notes, something that shows he's done a lot of research and spent a long time drawing up the plan.