1. High transportation cost: Xichang is relatively remote and the transportation is inconvenient, which makes the transportation cost higher, thus pushing up the price.

2. Insufficient market competition: Xichang market is relatively small and the market competition is insufficient, which may lead to imbalance between supply and demand of some commodities and higher prices.

3. The space economy drives up prices: Xichang is a famous space city, and the development of space economy may drive up local prices.

4. Higher cost of living in tourist cities: Xichang is a tourist city with a relatively high cost of living, which may aggravate the pressure of rising prices.

These are some possible explanations for the higher prices in Xichang than in Chengdu. The specific situation may be different due to factors such as market and commodity types.