It's a lot to do with triboelectric effects, static, IMO. Lay a cable on the ground, the physical parts are in tension from being orientated in a new position - over a period of time the materials settle into their new orientation, and 'relax'. Yes, the effects should not be audible but I've learned to worry about this - best is to use cables that have least worries with this.I'd like some tests, sneak into a audiophiles home and replace all his 'burnt in' cables for brand new ones or swap out some component..
It's a intresting phenomenon, even if it's just psychological I'd love to know what's really going on.