I recently deleted about 40,000 emails. Most of them were identical, duplicate marketing emails. I was forced to do this to free up storage.
That's when I realized something. I am paying my email provider for the full price for every byte of "represented" data. In reality, their distributed file systems could compress an arbitrary number of copies of these emails and only consume the amount of space that one email consumes. So 100,000 duplicate emails on the server are consolidated into one representation of the data, but each customer has to pay for each byte that is represented.
The vendor stores a file once and charge full price every time they reproduce it for someone. If you have 10,000 copies of a file they only have to store it once but you will pay for every byte in all 10,000 copies.