With a house, whoever legally holds the deed owns the house, regardless of who owns the key. If the deed is lost, there is still usually a backup trail of docs that correctly identify the last owner.
Until some government decides to expropriate "your" property and pay you what they decide.
Indeed, there is no real estate ownership. You just end up paying some one who can evict you for non-payment (a government) instead of a landlord or lender.