Bob Lutz:

I think we have to separate true luxury from what we broadly refer to as “luxury brands,” including Acura, Infiniti, Cadillac, and Lexus. Even BMW and Mercedes no longer fit in the first category. When people are paying $800 a month for a Tahoe LTZ and $350 a month for a Mercedes or BMW 3-series, which one is luxury?
 My favorite definition of luxury is the presence, in the product or service, of way more than you’ll ever need. It’s excessive capability, be it in size, style, performance, or features. That’s why a $60,000, crew-cab, turbodiesel 4×4 pickup with a leather and wood interior qualifies as much as a Porsche. But true luxury brands have to be expensive and relatively exclusive. I’ve always marveled at the battle between Mercedes and BMW (with Lexus as an also-ran) to be the top U.S. luxury brand. To me, it’s antithetical to be simultaneously exclusive and the most popular.