"http://Japanese carpentry was developed more than a millennium ago and uses distinctive woodworking joints. It involves building wooden furniture without the use of nails, screws, glue or electric tools"Well, collapsible equipment (whether metal or wood) would likely require a greater level of "tech" (metal working, precision tools, etc.) than is present in the D&D world.
But then again, maybe not? The actual level of "tech" in the D&D world seems to vary from bronze-age to early Industrial Revolution depending on what you looking at.
the cultural stasis of world like FR make such developments likely but FR is not the only setting. Eberron, spelljammer, & sigil/planescape almost certainly have had a wide range of collapsible equipment for so long that it's not even unusual in certain product areas to find collapsible versions where it makes sense. Darksun is another one that almost certainly had it just as common but now just has some of it to be recovered so it could be found even if nobody still knows how to make it.
While eberron is early industrial revolution yes, it's not our industrial revolution so some areas (ie metallurgy) they are going to be quite a bit behind while others are going to be above the curve we set (sometimes dramatically so). The enlarge reduce is only a second level spell & does quite a bit more than would be needed for shrinking a nonliving inanimate object so the enchantment needed to shrink things like a pair of skis/snowshoes/fishing pole/bedroll/etc could easily be first level or even cantrip level enchantment on the item. That folding boat might be rare in forgotten realms sure but the first three of those four settings might have an availability on par with our heavy duty inflatable rafts today because it's a simple enough enchantment to build in.