> A 2T SSD for $38 sound to good to be true and of course they are a scam, don't buy they don't work
But that's not even the biggest oversight here on storage, these drives also need to be attached to something which will need to be cooled, networked, and powered in a reliable enough way the service continues operating when you have 10s of thousands of these. You'll also need to store more than exactly the amount of data since you can't just lose videos any time there is a failure.
In all it's still going to be dwarfed by encoding and bandwidth costs but that doesn't mean 15k/PB is any less an order of magnitude or two off on storage costs.