When new in 1978, this Cadillac Seville went out the dealership for $15,000
whereas $10,000 were enough to go with contemporary full size Fleetwood.
The Seville, introduced in 1975, was Cadillac's answer to the rising popularity of luxury imports in the U.S. from Europe, such as Mercedes-Benz and BMW. Historically, these imported luxury cars had been cheaper, less luxurious and significantly smaller than Cadillacs. Over time they had evolved, becoming quite luxurious and even more expensive than the much larger Cadillacs. As the market share of these imports continued to climb, it became obvious that the traditional American automotive paradigm of "bigger equals better" was no longer in full effect in the marketplace. The Seville became the smallest and most expensive model in the lineup, turning Cadillac's traditional marketing and pricing strategy upside down.
Initially based on the rear-wheel drive X-body platform that underpinned the Chevrolet Nova (a unibody with a bolt-on subframe, common to both GM X and F bodies), the Seville's unibody and chassis were extensively re-engineered and upgraded from that humble origin and it was awarded the unique designation "K-body". , while small wrap-around rectangular tail lamps placed at the outermost corners of the rear gave the appearance of a lower, leaner, and wider car. The wrap-around taillights might have came from a design sketch of a rejected Coupe DeVille concept.
Sources : The Gentleman Driver & Owner, Wikipedia