From prices I can see it's 10-20x more expensive than tape archives.

Only if you are filling the tapes. For the average person bluray is much cheaper since they don't have much data.

if you have less data you buy older generation tapes, LTO-5 is 1.5 TB uncompressed and should be in price sweet spot right now.

	▲	bluGill 3 hours ago \| parent [-]
		Maybe. For the average person here though they will already have and want a blu-ray drive for "reasons", and so using it for backup is very cheap. LTO-5 might be cheap, but they still need to buy a drive that they won't use for anything else. If you are a business of course tape is cheap. Even then, a few usb harddrives are cheap as well and much faster.