Online backups for the truly paranoid

For my nearly 1TB backup size, this would cost per month the same as my Crashplan account costs per year. Why are all these linux friendly backup services (this, rsync.net etc) so much more expensive?

I think most people here are already well aware of Tarsnap... but I'm always happy to answer questions.

How is this different from using Duplicity with a PGP key and throwing it to S3/B2?