It means it's for guys that would have a mustang over anything else, no matter the performance or price.
I'm sure some car guys with collections might buy it, but I would guess these will go to guys with a stable, and this will be the ultimate Mustang. Jay Leno is likely a possibility.
I see it in many variances. Lots of guys buying only one brand due to loyalty or upbringing. I just think this model is an intelligent target at exactly those guys, who are a bit older now, and with some cash to spend on their favorite ride.