> With some amount of redundancy and growth that would be 24TB of drive capacity at least. You're looking at $250k in drives alone.
16TB drives are available for ~$150:
https://www.amazon.com/Exos-SATA-512E-%E5%86%85%E8%94%B5%E3%...
12,400TB is 775 16TB drives. Add 20% for redundancy and this is 930. At $155 this is > You also need almost 100 servers to host that many drives
No you don't, you put them in an array container, which will hold 24-48 drives, e.g.:
https://www.ebay.com/itm/226215269668
Those hold 48 drives, so you'd need 20 of them and they're ~$300. It doesn't even move the needle.
> Then they'd have to pay maybe $500k/yr for three sysadmins (including benefits)
Why on earth would you need three sysadmins? After the initial setup this is a part time job for one person, and you probably already have that person because they're the ones dealing with all the problems caused by unreliable cloud vendors and forced SaaS software changes.
> Then some amount for tape backups, connectivity, electricity, maintenance.
Tape is cheap. Universities already have fiber. Maintenance contracts are for bureaucrats, you just use commodity parts and then keep a few spares. Electricity is going to be some tens of thousands of dollars a year. This is all still "on the order of $100,000", i.e. the price has that number of significant figures. Then annual cost is actually less because the drives etc. will last for more than a year.