A well-organized system derived from binder clips works for small/medium scale collections of debound books. It's a quick and easy, and relatively cheap, way to "rebind" them in parts. The clips even provide good surfaces for labels.
Archivists recommend standard ambient conditions or a little drier for long term storage. As you've said, too dry and the pages fall apart; permanent damage.
I suppose the fancy silica gels that maintain specific humidities would work in bags.
My understanding is that the fibers in paper can become brittle if they are too dry. However, this doesn't cause the paper to break down, it just makes it vulnerable to damage if flexed. So storing paper dry is fine if it is then humidified before being stressed.
It's possible. My only experience is with vintage newspapers that were allowed to dry out, and then when trying to open them just shatter like a carbonized volcano scroll.
It's truly humbling how much knowledge professionals from different fields have, and how easy it is to fall into a Dunning–Kruger effect trap where a bit of knowledge — extremely extrapolated — would've led me down the path of hubris and guessing so many wrong answers. Thanks all.
>> If I did that I'd seal them with silica gel to keep the humidity down.
> I would think this totally dries the pages out and then they just turn to dust, from experience.
They used to sell Boveda two-way humidity control packs that would keep a bag at a constant low-ish 32% humidity, but last I looked those were discontinued (it looks like they've pivoted pretty heavily to marijuana storage and higher-humidity products).