It's not just H-D...but I will never understand why an industry releases its new product line IN THE MIDDLE OF A SEASON!
Okay, I'm better now.
The best time, IMO, for changing the model year of any motor vehicle, is in the peak of the riding season...motorcycles especially. Launching the new models in January, when half of the country can't ride, would not be as effective as launching in July. If you notice, the automobile industry traditionally launched their new model years in September, but now a lot of the Mfgrs, are moving their release dates up more into the summer; peak vacation/driving time of the year.