well its a giving fact that turbo's use the air leaving the engine to run and cause no loss of power that a belt would but as he said its all about being different, resource $$$$$, and daily driving conditions.
With the turbo tho, you have to keep in mind its the expanding heated air, not the flowing of the air that turns the turbine.
With the supercharger its just a pulley that turns a gear, turning another gear that pushes air. While compressing air causes heat as well, more parasitic loss is due to hot air entering the combustion chamber. This is more robbing of power than the supercharger itself. The gains with a supercharger even with the parasitic drag are still gains. The instantatneous torque increase in the lower rpm band is a major plus too, though. A big neccessity for a 4 banger. This can be accomplished with a turbo though not as efficiently.