Earlier quoted context omitted.
BitTorrent will solve the distribution problem but not magically provide more storage. Someone still has to foot the bill for storing gigabytes (or terabytes) worth of docker images.
Have a free client that seeds any images that you download, and a paid for one that doesn't. Now you have all those who don't want to pay providing your storage and bandwidth.
Tricky bit is, for some users, you’ll either abandon them with no way to share or you will still be paying their ingress/egress fees when their client falls back to your TURN server if NAT hole punching fails.
You’ll also have to solve image expiration gracefully. Hosting a “publish as much as you want” append-only ledger isn’t going to scale infinitely. There needs to be garbage collection, rate limiting, fair-use policies, moderation, etc. Otherwise you’re still going to outstrip your storage pool.