I think I'm understanding something wrong.  What error did I make
   below?
   Filecoin

   [1]https://file.app/
   $0.0292 / TB-Month
   Siacoin
   [2]https://siastats.info/storage_pricing
   $4.29 / TB-Month
   Amazon Glacier
   [3]https://aws.amazon.com/glacier/pricing/
   $4.00 / TB-Month
   It does look like things have changed since I noticed what was up a
   little.
   What's most relevant is that the fact that these chains ever let data
   expire is simply an artefact of their design: they could be changed to
   never let anything be deleted ever, and still pay people for storing it
   via mining and fees.

References

   1. https://file.app/
   2. https://siastats.info/storage_pricing
   3. https://aws.amazon.com/glacier/pricing/