I don't think GenZ and Millennials have the expendable income. Between college debt and a house mortgage the extra money just isn't there, even if they find the Harley's attractive.
They just aren't very good motorcycles. You can get almost any other motorcycle and they will be better to ride, more reliable and probably cost a lot less.
Harley Davidson also didn't modernise its brand. Also a lot of the image of Harley Davidson is attached to the heyday of motorcycle gangs, old movies between the 50s-80s e.g. "Easy Rider", "Electra Glide in Blue" and Music from that era.
