I just checked the price tag for LTO drives. These are a serious investment, and you can get a huge pile of SSD/SR drives for that.
What would the benefit of tape be here?
For large users (not amateurs or home users), the price of the drive is nearly irrelevant. The drive will be utilized for 5-7 years, it will be continuously busy reading and writing, and costs much less than the tapes.
So let's look at the cost of media. I will use publicly available prices: 20TB of disk (which is probably the sweet spot today in terms of $/GB) costs about $350, or $18/TB. LTO-8 media is $45 for 12 TB (I'm using uncompressed size, assuming that the software stack above has done maximum compression, usually a good assumption), which works out to $4/TB. With LTO-9, it is about $85 for 18TB, a tad more expensive at rounded $5/TB. The prices for 359x cartridges are similar per TB. That difference alone (little factor of 4 or 5!) is what makes tapes still very attractive.
Now, you might (correctly) argue that $1 in disk drive costs $5 once assembled into a server and connected to the network, costs $100 over its lifetime in power and cooling, and administration can (if one is careless) multiply that even higher. This is correct, and the growth (scaling) curve for tape is very different than for disk. Tapes that are not actively being read or written don't need power, don't need rack space, don't need network connectivity. To get anywhere near the same efficiency, disks would need to be powered down (that's called MAID technology, and exists in production, but in few places), and perhaps even physically removed to a vault (I've heard of that being done, but I don't know current production settings). On the other hand, tapes need a large investment in robot technology (the big StorageTek libraries cost about $1M, but they also held several thousand tape cartridges, and had a dozen drives). And archiving tape has a high overhead of physical movement: boxes of tapes need to be driven to/from the vault. The real cost of tape versus disk is a fascinating question, and depends very much on the expected access pattern. But the basic cost difference (of a factor of 4 or 5 today) tilts that playing field very much towards tape for archival and long-term storage.
