I believe they have overestimated the cost of using 3.5" floppies, probably to make themselves look better by comparison.
They give the cost as $211,172, but that's the cost to buy a 1 TiB pack of floppies. Their own storage cost is per-month, so to get the equivalent cost for floppies you need to also divide by the expected useful lifetime of a floppy disk. I did a web search for "floppy disk lifetime" and the internet [1] told me "I’ve seen numbers saying the lifespan of floppy disks is three to five years. But I’ve also seen numbers that claim they can last ten to twenty years or even indefinitely."
If you assume floppy disks have an expected lifetime of 5 years, you can amortise the cost across that time, bringing the cost per TiB-month down to a nice reasonable $3,520.
They give the cost as $211,172, but that's the cost to buy a 1 TiB pack of floppies. Their own storage cost is per-month, so to get the equivalent cost for floppies you need to also divide by the expected useful lifetime of a floppy disk. I did a web search for "floppy disk lifetime" and the internet [1] told me "I’ve seen numbers saying the lifespan of floppy disks is three to five years. But I’ve also seen numbers that claim they can last ten to twenty years or even indefinitely."
If you assume floppy disks have an expected lifetime of 5 years, you can amortise the cost across that time, bringing the cost per TiB-month down to a nice reasonable $3,520.
[1] https://blog.storagecraft.com/data-storage-lifespan/