For marketroid values of "archival"
Everyday use of the term means something I can save to, stick it on the shelf for 15 years and then say "Oh, I need to refer back to that" and have a better than evens chance of being able to actually read it. I don't think that is what they mean here.
It seems that every time flash begins to get anywhere near the level of reliability needed for that kind of role they jack up the capacity and lose everything they have gained. Perhaps more so - you could buy EEPROMs with 40 year retention guarantees since at least the early 80s. These days flash manufacturers seem to think they are doing you a service guaranteeing even five. Multi-terabyte flash drives are still a couple of generations off (at least in cost effective form) so it isn't even as if they are suggesting going back to tried and trusted tech.