Cadillac was once so strong as a brand that it became an adjective for best-in-class.  Today it has a brand problem.  Too many of its drivers are old and will soon age out of the car-buying market.  Over recent decades, German brands have trumped Cadillac on prestige in the traditional engine market, and Tesla is winning the electric market.  (Audi is fast following into electric cars.) Cadillac tried a reboot in the past, through advertising and moving the headquarters to Soho, NYC.  However, that did little in an age of transparency when actions define a brand, not spin.  The top-of-the-line GM brand began a more genuine reboot in 2018 when it moved headquarters back to its roots, Detroit, and appointed a veteran engineer as president of the brand. The brand is building for the long term, according to a recent NYT article, but let…