You make a valid point, and I don't think anyone other than BJ is arguing that buying and keeping long term is a poor choice... it's ALWAYS less expensive in the long run unless you have a nightmare lemon of a vehicle.
However, I will actually say that leasing has another advantage. With a leased car I don't have the emotional attachment and obsessing over every ding, scratch and rock chip that I have with a car I am going to keep long term. Not to mention all the aggravation of making sure that each and every servicing is done the right way, as I will be on the hook for the costs if something eventually goes wrong.
Quite liberating actually.