“Why Magico is made out of aluminum? Probably because it is cheap.”
Whether aluminum is cheap or not is besides the point. If you look at all the complexities in the internal bracings that are used and machining of all those pieces and the time and cost to assemble everything you’ll get a picture why they cost so much. It’s certainly hell of a lot easier (and cheaper) to run MDF boards through CNC machines and glue them up together, even when every other component, e.g., drivers, crossover parts, etc., are the same.