Ah, the good old 5 2/8 inch disc, a little more than 100kiB per side unformatted. Back before storage manufacturers realised they could cheap out by switching to decimal megabytes. I remember having a 1024MiB SCSI hard disc drive (presumably they thought that sounded better than 1GiB). I assume in terms of SD limits they're still using kibibytes and up because it's probably based on a binary addressing mode bit width, and I still have a labelled 2GB SD card, which I expect (untested) to have 2GiB. In this machine on the other hand I'm using a card labelled 128GB and it hasn't actually got that much on board (fdisc reports 119.1GiB, but 128GB requires 119.2Gib I reckon), but it still probably has more than an eighth of what this new card contains.
Edit: I don't remember a box of 10 5.25" discs costing all that much. I think they were about $20 for a box of 10 when I started buying them, although I wasn't an early adopter of that format. At that price though, you'd need buy just shy of a half a million of those boxes to match the size of this, which would cost you something like $2mil (although I assume you could probably get bulk buy discounts at that scale).