My friend's hypothesis is that it is all marketing. For example, the bulbous windscreen currently on my K1200LT (made by Aeroflow) is the most effective windscreen I've EVER used... but it sure is funny looking. The stock windscreen looked far more "sleek and sexy" on the showroom floor.
Just look at all the European Tmax riders with their teeny-tiny "cool" sport windscreens. Not only did the OEM screen not work worth a damn, but the Sport Screens are essentially good for looking nice in a photo shoot. You're sitting in a semi-touring position on the Tmax, but also have to lean into the wind blast over 30 mph with a sport screen? What cost your Boy Racer image?
The "weird-looking" GIVI Airflo that fits TONS of bikes works amazingly well, but I've only see 2 or 3 EVER on a Euro Tmax. Those riders say that "sure, it's ugly, but boy it works well"...and their friends rip on 'em...
KYMCO made the same mistake with their new Xciting 400i. In a four-way test, it placed third, but the writer said it would have WON...with a better windscreen, instead of the tiny factory Sport Screen...
You CAN"T have it both ways...want a Sport Bike? Buy one! Don't try to make your C600, or Tmax 530, etc. act like one...it CAN'T...