I think there's something to the OP's point.
Amazon's infrastructure roll out paid off in the United States because there was little competition. They rushed out infrastructure and cornered the online shopping and delivery market. Walmart and the other big stores had an entirely different business model and their warehouses and infrastructure took time to adjust and catch up, with Amazon still in the lead.
In China, the local competitors already have a significant head start on their infrastructure, and Amazon would be playing catch up in a relatively unfriendly market. It could take them forever to recoup the investment, if they ever did.
Unfortunately, they can't compete without that infrastructure in place, so what else can they do but leave?