Netflix is a counterpoint? A good fraction (though not majority probably) of their cost is probably bandwidth and computation yet they continue to offload that to a cloud provider, who's a direct competitor no less.
netflix does not serve their bits over amazon. they have their own major infra, and operate a large and distributed cdn, including edge caches colocated within eyeball networks.
it would be insane for them to deliver their video content over aws.
Netflix does run their own CDN for video content, presumably to avoid that exact problem. I would imagine that's by far the most expensive part of their business.
By some measures, that's much more extreme than running your own datacenter.