Completely untreated wood stored in a dry environment will last many years (hundreds? tens at least) without degrading. Look at woodworkers hoarding wood in basements, beams in old buildings, etc

Staining/waxing/varnishing is used to protect the surface from wear and tear or change aesthetics. A varnished table that has been worn through in areas can be sanded back and look like new. The wood under worn spots won't be noticeably different.