Compared to what, exactly? Tape is cheaper per GB, but the drives and libraries tip that over the other way. Blu-Ray discs are now more expensive per GB than hard drives, thanks to SMR and He offerings.
Also note that Backblaze does backups -- by definition, these are infrequently accessed, usually write-once-read-never. I've personally been a customer for three years and performed a restore exactly once.
Despite claims to the contrary, tape isn't dead just yet. They are still considerably cheaper than drives. An LTO-8 tape (12TB uncompressed capacity) can be had for about $100, while a 12TB HDD goes for some $300. Tape drives/libraries are quite expensive though, but that just shifts the break-even point out. For the largest sites, its still economical. Not sure, if backblaze is big enough (I'm sure they did their numbers). backglacier anyone?
And a number of the library vendors' libraries last for decades with only drive/tape swaps along the way. The SL8500 is on its second decade of sales for example. Usually what kills them is the vendor deciding not to release firmware updates to support the newer drives. The stock half inch cartridge form factor dates from 1984 with DLT & 3480. Given there have been libraries with grippers capable of moving a wide assortment of DLT/LTO/TXX/etc cartridges at the same time. Its doubtful if that will change anytime in the future. So if you buy one of the big libraries today it will likely last another decade or two, maybe three. There aren't many pieces of IT technology you can utilize that long.
I bought a pair of 12tb drives for $199 the other day and they often go cheaper. Now admittedly if you shuck externals you loose warranty but we are keeping them in the enclosures as these are for backups and thus the ease of taking them off site is great for us.
Are you asking for service for the drive itself or for the drive within an enclosure?
Let's say you buy a Ford Explorer SUV. You remove the engine and use it somewhere else for a few years. If that engine breaks within the warranty period of the SUV, can you take just the engine to your local Ford dealer and ask them to fix it? Probably not.
Arguably, you can put the engine back into the SUV and take the entire car to a Ford dealer for repair. But would that constitute fraud on your part?
I was specifically thinking of the SKUs - I assumed they were using faster disks rather than high volume disks that make trade-offs for costs. Just assumptions on my part - and I am mostly curious for more data, but given the historical trends, I'm not terribly suspicious of the actual results here.
Drive enclosures, raid/etc interfaces, and motherboards burning electricity make it a lot more complex than raw HD's vs raw tape. Tape libraries cost a fortune, but so do 10+ racks of cases+power supplies+servers needed to maintain the disks of equal capacity.
Tape suffers from "enterprise" which means the major vendors price it so that its just a bit cheaper than disk, and they lower their prices to keep that equation balanced because fundamentally coated mylar/etc wrapped around a spindle in an injection molded case is super cheap.
Also note that Backblaze does backups -- by definition, these are infrequently accessed, usually write-once-read-never. I've personally been a customer for three years and performed a restore exactly once.