The flagship Cadillac CT6 sedan never quite managed to find its footing in the US market, despite plenty of brilliant engineering and a sticker price thousands below those of its European competitors. Ultimately, most of its innovations and capabilities were not immediately recognizable by cross-shoppers looking for a more luxurious interior.

The full-size luxury sedan market isn't one that General Motors is likely to want to reenter any time soon, as the market's focus shifts ever more toward utility vehicles and away from traditional sedans. Cadillac President Steve Carlisle said as much earlier in the month to CNBC, telling the outlet that no Cadillac CT6 replacement is currently in the cards.

If Cadillac does produce a follow up to its large flagship sedan, however, it will likely be a pure-electric car, Carlisle says.

"We're headed into this intensive electrification cycle," Carlisle says.

"We're going to enter this decade as an internal combustion engine brand. That's where we are. We've never been better positioned as an internal combustion brand," he remarked during a media event. "It's a decade we're also going to exit as a battery-electric brand."

The CT6's discontinuation without an internal combustion-powered successor spells a more definitive end for Cadillac's twin-turbocharged 4.2L dual overhead cam V8, dubbed "Blackwing". There are no plans to fit the motor into the brand's new top-dog performance sedans, based on the new CT4 and CT5, likely because its large external dimensions present issues for packaging.

Cadillac previewed what will be its first battery-electric vehicle in January of last year, releasing images of a sleek, almost Lucid Motors-esque crossover. In other words: if an all-electric large sedan ever does materialize, it won't be first in line. That leaves the release timing of such a vehicle a complete mystery.

Cadillac's current plans call for transitioning to mostly or entirely a pure-electric automaker by 2030, including all its passenger vehicle models sold around the world. On the one hand, the quiet, smooth, plentiful torque typical of electric powertrains is a natural fit for a luxury brand.

On the other hand, we'll never forgive Cadillac for not producing the absurdly huge, ostentatious, V16-powered Cadillac Sixteen concept of 2003. What a shame.