Magnetic tape manufacture is dirt cheep compared to everything else, $64 million in manufacture equipment would be pretty big

Tape is not a new-old technology. Just a hidden tech only bigger companies utilize and the common citizen only comes into contct with as the IT tech of the company.
Cheapest most secure way of doing WORM backups.
S3 can do WORM as well but Tape can't be hacked ¯\_(ツ)_/¯

Probably for storing large training data libraries. Takes vast storage, but only need to be periodically accessed during training run on that specific part of library. Once the training is done, there is no need to have online access to the data.

Plus with tape drive library robots, it's not like they have to be manually handling the tapes often.

The Internet isn't static or 'forever' like people like to joke. AI companies are slurping up data and they need somewhere to keep it. Hard drives are already increasing in price and they still need to store long term things like all the books they are destroying.

As some comments here have pointed out, it's probably more like data that goes into the training corpus.

I'd also suggest that some demand won't be from AI companies, but rather from other consumers of data storage, even if a boom in AI-driven spending is at the root of things. Like, maybe your ideal storage medium is SSD, but AI-related demand has driven prices up to 5x what they were earlier. Okay, so some users get priced out and fall back to rotational drives, because those are good enough for their use case. Prices on those go up by 2x. Well, the next fallback for some of those users who get priced out, who maybe used hard drives to store backups, say, is gonna be magnetic tape storage.

This is likely for archiving the Internet before AI flooded it with slop.

Archival of everything being scraped before its pushed off the internet and replaced with AI produced garbage.

They don’t need to archive AI output silly, they need to archive the cumulative works of the internet because they keep forcing hosts to shut down with what are among the most aggresive web-crawlers ever deployed outside of DoS attacks.

This feels like a brain dead comment.

Why bother archiving anything when a computer can produce it?

Because sometimes it's faster or cheaper to compute something and store the result then to recompute it every time. Nothing about AI changes that or is special in any way shape or form.