So multiply it by your download speed. Let me know when you get to $22k.
I assume the cost is in retrieval though and counted per the Job Creation API, regardless of whether and how quickly you download the data.
but you're right that the 3TB/hour use-case is very hypothetical. Internet archival is just not suitable for those kind of volumes. I think the point OP was making that mistakes like using archives that are too large, or requesting many at once could cost you a lot.
If you actually USE 10gpbs your data transfer bill is going to be around $167k per month (That's for transferring 3.34PB).
Actually, a bit higher than that since I calculated all based on the cheapest tier EC2 will quote on the web, 5 cents per gigabyte.
For a one time 3TB download to an EC2 instance, priced at the first pricing tier of $0.12/gigabyte, that transfer will cost $360, and take around 40 minutes.
There is a huge difference between a residential connection with a peak speed of X and an X speed connection.