Whenever I see a brand-new Cadillac driving around (with or without temp tags) I can't imagine the driver buying it for any other reason other than they wanted a supposed swanky badge, but it absolutely had to be an American car; the 'Murica mindset. Otherwise, I'd imagine they'd run to the nearest Jap or German car dealer. I know I would. I feel the same about Lincoln. Although, Lincoln does make arguably more exciting cars. Which isn't saying much because some of their vehicles look (to me anyway) like odd mashups of styling cues from Euro-lux makers that Ford used to own, mixed with Audi. Actually, Ford's whole lineup is like that.
One of the biggest issues I see with Cadillac, is the fully loaded lesser-brand equivalent seems to be a better value. It makes you wonder if the lesser car is really well built for what it is, or the Cadillac isn't all that. That's pretty sad. For example, prior to buying my new Jetta, I cross-shopped the Mazda 3, Jetta, and Mini Cooper four door, with one-year-old CPO, A4, C Class, 3 series, Q50, TLX. I wound up with a new Jetta. While I love my new Jetta, I can totally see why an A4 costs more; they're quieter, sportier, better screwed together, nicer materials, slicker tech, faster, etc... Comparing a fully loaded Chevy or Buick to a Cadillac is a totally different thing. Neither of them really feel better than the other one. That's a problem when the Cadillacs cost quite a bit more. What exactly are you getting? Other than different styling or badges?
I think in total, American luxury is an outdated concept; they failed to compete with the almighty Japs and Germans in all aspects. Marketing, the actual product, you name it. These things matter. In all honesty, I wouldn't be surprised if American car makers become strictly pick-up truck producers. After all, that seems like the only thing they do right.