Land is not an investment (at least, not without explicitly improving the land). Buildings depreciate. If land (or the buildings on the land) are returning anything close to an index investment, an economy is seriously sick.
Edit: yes, you can rent the property out—but, societally, that's just shunting the problem down the road.
Edit: yes, you can rent the property out—but, societally, that's just shunting the problem down the road.