Cotton laundry bags are readily available and make a great storage bag.
I'd never store any of my sleeping bags stuffed/compressed...but I expect them to last (and they have) for more than 20 years.
Every manufacturer's care instructions that I have seen recommends that down TQs/bags should be stored uncompressed. They typically warn against loss of loft if left in a compressed state for a long time.
I've read both, one can store their bag compressed or uncompressed.
Personally, I used to have a Wiggie's bag. I always stored it compressed on and off for 3 years. I never felt that practice affected the bag's thermal properties. Wiggie actually markets that his bags can be stored for years in vacuum compressed/sealed bags and then be deployed without issues.