Part 2 of the HD marketing equation is why spin-offs don't work. It was in the mid 70s that Honda came out with a small displacement model that was styled like a HD. I remember a bunch of us laughing about it and the salesman saying it was very popular with the 'low SES' crowd. Likewise, an old buddy who owned a Honda cruiser said he sold it because he just didn't feel right pulling up to a stoplight with a group of Harleys.
For good or bad, HDs reputation rests on them being Harleys and a breed apart. Riding a 250cc Chinese V-Twin is like a kid with cap pistols and a red cowboy hat acting tough in a Marine barracks. Even the guys who don't like HD will have to wrestle with taking them seriously. I suspect that the biggest threat to the HD brand is how some HD based clubs are marketing themselves as "family oriented". The day people believe that "you meet the nicest people on a Harley" is the day they will have lost their mojo and their market.