I assure you there is nothing sinister about the price asymmetry. Fiber and routers have as much bandwidth coming as going. The inbound traffic is mostly composed of little http(s) requests. The outbound is full of images and mountains of JavaScript. Cloud providers don't charge for ingress because they got it for free when they grew their egress capability to meet demand.
They don't own many of their data centers. Locations were leaked a while ago, most are colocated in major data centers. They won't dig new trenches and lay cables between those but rather negotiate rates for existing fiber.