For a sports car i agree, smaller works out more, like an M3 or RS4, C55...
But for a lover of big luxury cars, there is a huge market for that, and power becomes everything amongst the size and comfort of the car... Hence S55, 760i, S8.
Based on your post, those cars are just not needed, and they should have stopped at S500, A8, 745i. imo as well.
