Because people along the route had realized that there was demand and quickly organized supply. That's so Chinese. In a well-organized country like Germany, such a problem may not have arisen in the first place, but in China people immediately recognized an opportunity.
When I was still in prep school - 14, 15 - I started keeping notebooks, journals. I started writing, almost like landscape drawing or life drawing. I never kept a diary, I never wrote about my day and what happened to me, but I described things.