MT noted a few are long in the tooth, some are from another era, and damn near all of them a part of or the basis of some kind of badge engineering.
The Cadillac XLR for example is arguably all three. A remnant from the "V8 is king" era, has been on the market for what seems like a decade now, and it's underpinnings can be seen under a Corvette. As nice as the Corvette is (essentially being the best America has to offer), the premier offering of America's foremost luxury brand deserves better. Like something bespoke.
The Ford Explorer and its variants are still body-on-frame and the Pontiac G3/G5 are Chevys. Note the former's being replaced by a crossover while GM, hopefully, will stop the rebadging that is the latter.
The Lincoln Town Car should get a break though for being the perfect basis for the stretch limo. The Lincoln MKS, on the other hand, is thoroughly modern as the brand's new flagship.