That works. It is important for Sui or Tang to build a closer trade relationship with interior China so there are some incentives to maintain the land and the connection.
For instance, Western Han was interested in Central Asia due to local horses and political and military alliance against Xiong Nu. The horses from central Asia were taller and stronger than horse from interior China. As a result, soldiers were able to wear heavy armor for protection while riding the horses from central Asia.
I am not sure what were goods from Iran that were essential to Chinese economy. If there were some, there would be a huge incentive for emperors and governors to sinicize the land regardless the resistance (much like southern China in Tang Dynasty).