I wouldn't generalize too much from one case of black silk. I guess there were various methods of dying fabrics black. Mariano Fortunay "Delfi" dresses are know to still be intact with out restoration work. They came rolled up in carboard boxes and to keep the crepe fabric nice it was recommended they were to be stored in the same way. Get the right quality carboard and tissue paper for the purpose and this storage technique works. There are odd cases were old silk garments have been found in unusually good shape, sometimes they have decided to keep on storing them in the same place because of the favorable conditions. In museum storage they are kept in special closets and drawers, in rooms with controlled humidity and temperature, but still wrapped in tissue paper.
A lady who worked with fabrics at a museum, (clothes, carpets, curtains,...) gave this instruction for someone who wanted to take care of an old item; it was either the cardboard box method, and another way was; To wash a white 100% cotton sheet on 95C with washing powder, then another round in the washing machine at 95C with out any detergent. This was to be dried with out being ironed just strethced and smoothed out when wet. You had to go through the double wash even on brand new sheet as well as and old sheet you might have. The point was to have reasonably sturdy woven cotton with out traces of fabric softeners, detergents, or anything left over from production. It had to be white and no dyes in the fibers. The garment you wanted to store safely should carefully be rolled up or wrapped in the sheet. It was an alternative when it was difficult to fit things in a box or store a large enough box.