Mostly because insurance is so ridiculous it's just a massive waste of money and headache.Apparently you haven't noticed that the urban hipsters are crazy about old iron-head Harleys, Triumphs, and CB Hondas? Exactly the bikes their parents and grandparents rode. What they really seem disinterested in is cheap plastic death-rockets.
according to latest financial gurus's , millenialls now have more discretionary income than the boomer generation. Not finding a way to access that spending group would be silly, 500 & 750cc HD's , the bonneville lineup, ducati scramblers, "new" bobbers, all clearly aimed at 25-40yr olds.
HD didn't put a pop up cafe in the middle of ground zero hipsterville by accident. That's their future.
Only way this is true IMO would be because housing prices are so crazy that most of them just give up and the money they would've spent on that becomes discretionary. I know my discretionary income would be way lower if I had maintenance on a house and mortgage to pay but since there's no way I can ever afford a $1.5 million home all that money goes to toys and vacations!