Innovative CT6 becomes another Cadillac relic

DETROIT — The CT6 was supposed to be the flagship sedan that led Cadillac's rebirth. It was the first full-size Cadillac with rear-wheel drive in two decades, the only Cadillac offering a high-powered Blackwing V-8 and the only way to get Super Cruise, a driver-assist system that many critics say outperforms Tesla's Autopilot.