Let's say a 100 exabyte, which is only 100 times larger than Backblaze. And Amazon pay $100 per 10TB, it is unrealistically low, but just to round down the number nicely . ( It is not $50 for 10TB, part of the reason why HN dont understand Supply Chains and BOM cost. )

On pure storage that is 100,000,000TB. That is 1 billion dollar already excluding any redundancy required by S3.