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.
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.
You have to take into account that there aren't (or very few usb) LTO-5 enclosures. While you can potentially find an LTO-5 drive >$200 these days, you also need an equipment with SAS or 8GB FC interface to be able to use it.