My response was in the context of someone who didn't do any of that.
Also, my tongue-in-cheek response to you is: the price will be offset by the SRE engineers who were babysitting your AWS setup that you'll no longer need. (More seriously, I don't think finding quality sysadmins who enjoy this stuff is particularly harder than finding quality roles for any other tech positions).
But it's not about price: It's about control, and it's about the expertise you gain from running all of that. If you have 10PB of data, you should have someone in-house who knows how to work with 10PB of data at a low level, and the best way to get that is to employ people at all levels to make that work. You gain significant advantage from having the direct performance data and the expertise of having techs whose 9-5 is replacing disks.
I did and you ignored all of it -_-
* To store 10+ PB of data.
* You need 15 PB of storage (running at 66% capacity)
* You need 30 PB of raw disks (twice for redundancy).
>>> At retail, 625 16TB drives is $400000.
That's only 10 PB of disks. That's about one third of the actual need.
Please triple your number and we will start talking. That's about 2000 disks and well above a million dollar.
You can't just call a supplier and get for a thousand 16 TB disks (or even a hundred). They don't have that in stock now. The lead time might be 6 months to get a few hundreds. They might not have 16 TB disks for sale at all, the closest might be a 12 or 14TB.
Handling large amount of hardware is a logistic problem. Not a cost problem.