As I see it, one of the biggest problems with your initial premise: because YG is still using aluminum drivers, therefore they are not innovating, is missing many other pieces of the entire story.
How do you know, that just because they are still using aluminum, they haven't innovated and improved: the overall geometry of the cone, the precision in manufacturing, magnet material and/or magnet geometry, decreased the mass, decreased resonances, improved performance of the surrounds, etc.?