I really wish a multi-terabyte optical media solution took off, because that would be the path I’d ultimately take, instead of going with expensive LTO devices and media.
Optical just didn't make sense to me. Overall it was way more expensive, and a lot slower to burn BluRay discs.
The max BluRay disc size is 128GB (which is smaller than a lot of SD cards these days), and the fastest you can write to a BluRay disc is 18MB/s. That's a lot of of swapping discs to burn my many Linux distros.
And those 128GB BluRay discs cost between $30 and $40 each. Used tapes (with a lot of life left in them) on ebay are far less expensive per TB - the lowest I've paid is about $1.40/TB for LTO5 tapes without a case. I typically pay about $4/TB for unused LTO5 tapes with a case on ebay. It's getting a bit more difficult to find those deals, but they come up every now and then.
The bigger problem is finding a drive that can read and write them -- the 128gb format support is a bit harder to find. I thought I would be good with my nice Pioneer BDRW drive but it didnt have the support so I had to buy an LG unit. So now my desktop has two BDRWs -- how very 2006!
The LTO5 drive cost me about $150 on ebay, and an HBA card was $30. Yay for datacenter hand-me-downs.
Tape reigns supreme in cost per megabyte, but the infrastructure costs are astronomical.
SD card is an atrocious archival/backup format as data retention is rated in low single digit years - though I am continuously amazed I can store 100GB or more on something so tiny. I would love a true archival SD card format.
A used LTO5 tape drive cost me $150, an HBA card cost me $30. That's literally the only "infrastructure" I needed to acquire. The tape drive has been running fine for several years. It lives in a tower PC, so I'm not sure what astronomical cost you are talking about. Sure, a new LTO-10 drive costs $20,000+ but I don't need the latest and greatest. I just need cheap, fast storage.
Unfortunately I don't have either a tower PC or a server in which to install it, being predominantly an iMac/Laptop user - so would need to factor in an external enclosure which are certainly not cheap.
It feels to me the broader issue is that consumer archival media is dead, with the (dying) exception of optical disk. I would love consumer tape drives to become a thing again - lower capacity, smaller, and USB-C connected.