Whenever a story is written about winged cars, there's always the obligatory mentioning that some of these cars languished on dealership lots for long periods of time, which is correct but only in a limited context. Most of the cars sold quickly, but we rarely hear about those, just the few that didn't sell. And of the no-sell cars, there's never any mention how a lot of these cars didn't sell because dealers kept them for their own personal cars and later sold them on the secondary market, or some dealers, like St. Augustine Chrysler-Plymouth, found the cars brought in so much walk-up traffic they kept their cars in the showrooms for decades (SACP's 440-6 Tor Red Bird was in their showroom window until the 1990s).
I got to work with the head of the Mustang production line in 2001. He was a naval reservist and I worked with him over at Kadena, Okinawa while he was doing his two week ACDUTRA period. He told me a lot about how the falling sales of Mustangs had been attributed to prices, fuel costs, demand for trucks, poor economy, etc., but when they quit talking to industry analysts and started talking to owners they found the problem was actually that the Mustang had stopped looking like a Mustang, which was why Ford decided to start redesigning the model to look like the most popular car with Mustang owners, the 69-70 cars. He also told me there had been a near disaster in 1986/87 when plans were underway to redesign the Mustang as a FWD car, and the owners revolted. Ford decided to continue the Fox body cars, but rather than scrap the new Mustang design, they decided to rename in the Probe. Can you imagine how Mustang enthusiasts would have reacted if the Probe had been the new Mustang?
I was working for Ford in 2004 when the redesigned Mustangs I had heard about in 2001 came out, and the response was like nothing anyone had ever seen before. Every 2005 Mustang to be delivered for the first six months was pre-sold, and that was at full MSRP and with a 25% dealer premium for base cars and 45% premium for GTs added on! We were selling GTs with an MSRP of $26,000 or so for close to $40,000 and people were going on waiting lists to buy them. We couldn't even get a hold of floor models and ended up having to rent a base and GT from customers just to keep a car on the floor.
Meanwhile over at GM, they had decided there was no more market for high-performance cars back in 2001, and quit production of the Camaro in 2002 while Ford was redesigning the Mustang. GM cut their dead wood loose, and managed to do it in a way that screwed over the UAW and made them look bad to the rank & file, so it was a win-win for GM. But then came 2004/2005, and the new Mustangs gave them the Oh Crap moment that drove them to start plans to reintroduce the Camaro with a late-60s design. Rather than wait for a design to be developed like Chevy was doing, Chrysler just took the next car coming through the design process and slap a retro name to it, Charger, which is why the next-gen Chargers didn't look anything like an old Charger and had four doors. It wasn't until the first redesign that we saw the car start to look like a Charger, but they did learn their lesson and do the Challenger right. I would have loved to have been a fly on the wall in the Dart II production office.

It seems like the lesson they learned was you can get oldsters to buy a generic sedan by slapping a retro name on it, so why not try the same thing with a low-end compact? Throw in a Ford Focus-inspired youth marketing scheme, and voila! I guess their plan isn't going to well.
The problem with having a trend-setting success like the 2005 Mustang is the people who brought it about get promoted to other jobs or hired away to other companies, and are replaced by new folks who want to put their own mark on things... enter the upcoming mess known as the 2015 Mustang.

It's a FWD car that looks like someone took a mid-90s Celica and put early 60s Mustang lines on the door panel. Anyone think it's going to be a doorbuster like the 2005 models? Maybe the guys who thought it was a great design, but I doubt many Mustang fans will. It looks like the automakers are going to be living through the old adage of "those who fail to learn from history are doomed to repeat it" once again.