I feel like something like www.storj.io is on the path to what we would want/need?
There might be some additional requirements for a true CDN to ensure data is closer to where it’s needed and in as many regions as needed though with the right amount of bandwidth. The data gets stored all over the place, but that doesn’t mean its optimal. But they do seem to claim it’s faster on their website…
Edit: For those not wanting to click, TLDR is they use excess storage around the world and make it accessible anywhere, and safe from failures. People with excess storage can join the network if they have enough storage/bandwidth and pass some tests. Their API is S3 compatible.