Identical Properties
Imagine you're looking at two identical properties, one is three years old and one is just starting to be built. The one that has been around for three years has an overwhelming amount of amenities (gourmet restaurants, spas, high end retail shops, etc) while the new development doesn't have any amenities yet. Because of this the price on the new condo (The preconstruction development) is significantly lower and thus more affordable for the investor. Now after this condo development is completed amenities will stop popping up around it and it will then be worth as much as the original condo that has been around for three years.