I think it's a complex of things. Local air quality and weather combined could ruin the finish on some cars. All Stingers? Time will tell. I have my car in the shade all the time that it isn't driven. At most, it gets a tiny bit of sun first thing in the morning and late in the evening in the summer, and even then only on its "tail feathers". When a car is outside every day all day it will age faster; inescapable fact. This is when a ceramic coating is king.
You could try wrapping your dark chrome strips. That wouldn't be very expensive and it would spiff up the appearance with minimal effort. Then ceramic coat the entire car.