So urethane sheeting on the outside reduces that stud loss a great deal. Vermiculite is one. We used to buy it in bags and pour it in between the joists in the attic. If you've ever taken a ceiling lamp down from a ceiling backed with vermiculite, you'll know it because you'll get a shirt full. It's a natural mineral, loosely granulated like rice.
Nurseries use it as an additive to potting soil.
Older still, in terms of use, is rock wool. That was a heavy material that hung up a lot if nails and wire and plumbing were in the walls. It depended on the air space around the material, because rock wool itself is not a very good insulator. It's usually black and quite dense. It's very heavy, dense and dusty after all those years.