The sum of the stories seems to be that there are LOTS of reasons for the a vehicle to remain unsold at the dealer. To throw 2 more out there, there's a white 1976 Eldorado Convertible sitting in the showroom of the local dealer that's still on the MSO (Manufacturer's Statement of Origin), never titled. It's been out of the showroom a couple of times for remodeling work on the building, but has less than 5 miles (I've seen the odometer myself), an has allegedly never left the lot since it rolled off the hauler.

My own story was a 2013 Mini Clubman ClubVan. These things are big sellers throughout Europe, and Mini decided to try selling them here (full story HERE). Because of the Chicken Tax they only imported 50 of them. I found one in 2018 that sat on a dealer's lot unsold until 2015 (over 2 years) as verified by both CarFax and the warranty information from Mini. It was still under factory warranty (4 years) when I bought it.