And in recent years, automakers have moved the reveal of new models to the periphery of the auto show, choosing locations away from Cobo Center and on dates not directly coinciding with the press preview days of the show.

On Jan. 13, one day before the press preview begins, General Motors Co. is unveiling its new three-row Cadillac XT6 crossover at the Garden Theater — three miles north of Cobo Center.

"Utilizing auto shows as the exclusive location to intro cars; well, we now have a long history of deviating from that," said Terry Rhadigan, GM's executive director of product and technology communications. "NAIAS gets to count that as a world debut, and that's fine. Would they rather have (the reveal) inside Cobo? Probably so, but right now we think it's a better return on investment to do somewhere where we create and control the environment. We've got limited resources and always a lot of vehicles to unveil, so if we can do it for less money with the same or better impact or media coverage, that's our practice."

This strategy exploits the digital era, where automakers can dominate headlines and social media exclusively for a longer time than if an unveil happened on the auto show floor during press days where unveils are packed into 30-minute press conferences one after the other. As soon as GM unveils a product, that news is quickly swept aside for Toyota's, or another automaker's, unveiling.

BMW, which will be absent for the 2019 Detroit show, unveiled its sixth-generation M5 in a video game last year before showing the physical car to journalists at the show in Frankfurt, Germany, in September.

"We're reviewing the auto show footprint to say, 'Where does it really make sense, which formats make sense, to get journalists, to get customers, to show and display your vehicles?'" Bernhard Kuhnt, CEO of BMW of North America, told Automotive News. "We're definitely going to invest into other formats as well. The auto show is not the right format only."

The use of off-site venues is a major reason the auto show is moving to June in 2020. Show organizers hope to make use of Hart Plaza near Cobo Center and other close-by venues to expand the show's footprint and offer automakers the exclusivity they desire, Alberts said.

"You're going to see dynamic displays inside and outside of Cobo," Alberts said. "We're building this to engage the city and customers wherever automakers want to be in the city. The outside displays will be a complement to what's happening inside, which will be similar to what's always happened inside, increasing the ROI for automakers."

Alberts said the 2019 show, while missing the German automakers, is designed as a transition point for how the show will be in the future. The more than 100,000-square-feet once inhabited by Mercedes, Audi and BMW will be parceled to other automakers looking to expand, but some of that space will be used by two automakers in modified ride-and-drive activations, Alberts said.

Alberts declined to provide which automakers will operate the displays, but said they will focus on active safety and autonomous systems.

For GM, changing the Detroit show's format and date may save it from irrelevance.

"This is a total reimagination; it's bigger than they went to an international show in 1989," Rhadigan said. "Over the course of 30 years, things change. We've all felt it. The last few years, it felt like there were no surprises. The energy is gone. I think this is a bold move that could be a tremendous transformation of the Detroit show and auto shows around the world."

The risk, of course, is making this year's show an afterthought during a time of transition.

"It's natural for interest in 2020 to be heightened going into the last January show, I think," Brinley said. "It's also true that the 2019 show will have fewer automaker displays and press conferences than in 2018. But I'm certain it is not an afterthought to the automakers presenting."