Guns that are used hard and taken proper care of last a long time, they don't get all rusty, they just get finish wear and maybe dings in the stock etc. Actually the best storage system I have seen is the pistols hanging on pegs in a gun safe or other enclosed cabinet. But in a dry area, not in a basement where the walls weep water or something. Or on some kind of rack in the gun cabinet. Zippered cases or even synthetic holsters can work if the gun is stored in a dry area like a closet gun cabinet. Still should be examined regularly and wiped down. Maybe silicone from wiping with a silicone cloth would be less prone to leaching off the gun in storage? Like I said I can bear to see blueing wear but rust or pitting on a gun just turns me off to a deal. Of course collectable antiques for show are not the same as functional guns.
Your gun is like your nose, it is just wrong for someone else to pick it for you!