Wouldn't a person expect the difference between leasing and buying to be pretty small?  After all, you are achieving the same thing either way, so the cost has to be close or else the higher priced way would be used by no one. 

The thing that many people fail to realize is that the dollars paid three years in the future are only worth about 80% of what a dollar paid today costs.    This difference becomes much greater when you increase the interest rates and add in some inflation.