PARIS/FRANKFURT -- Frankfurt's vast auto show, which opens next week, is already getting attention of the wrong kind - for its impressive list of no-shows.
Besides the glaring absence of Tesla and its electric Model 3, the roster of big names staying away has grown this year to include such venerable brands as Nissan, Peugeot, Fiat, Volvo, Jeep, Mitsubishi and Infiniti.
The uncertain fortunes of the traditional car show mirror those of an industry in flux, its incumbents threatened by emissions regulation, tech giants and the sharing economy.
"Car shows need a new approach," said Patrick Koller, chief executive of Faurecia, a supplier with 19 billion euros ($23 billion) in global sales. "Otherwise they will disappear."
Frankfurt and Paris host two of the world's biggest shows in alternate years, punctuated by the Detroit show in January and other events in China, Japan, the U.S. and Switzerland.
But many of the traditional gatherings have seen visitor numbers fall since the turn of this century, when most new cars were still unveiled under their lights, framed by show girls.
The decline may be accelerating. Paris attendance was down 14 percent last year - with fear of attacks also weighing on tourism - and January's Detroit show drew 9,000 fewer visitors.
The sense of upheaval is acute in Germany, as Frankfurt prepares for its first car show opening since the Volkswagen Group emissions scandal blew up. Days before the event, Chancellor Angela Merkel was urging local officials not to ban diesels, as her re-election campaign drew opposition fire over perceived government coziness with the industry.
But diesel scandals are just one of the problems challenging automakers and the legendary largesse of their trade shows.
The emergence of tech as the main battleground for the connected, autonomous cars of the future has drawn exhibitors to competing events such as the Consumer Electronics Show (CES) in Las Vegas and Mobile World Congress in Barcelona.
The static nature of traditional auto shows held in convention centers is also being challenged as automakers opt to be a part of other colorful outdoor events such as the Goodwood Festival of Speed in the UK.
Footfall is becoming less important anyhow. Thanks to social media, Daimler reckons its Mercedes-Benz innovations reach the same global audience of 1 billion whether unveiled in Frankfurt or at CES - a trade-only show closed to the public, with less than a fifth of the German event's attendance numbers.
"Daimler's media strategy has changed with the rising significance of tech," spokeswoman Bettina Fetzer said.
Although Mercedes will be out in force on Frankfurt's 200,000-square meter show floor, it is "getting more complex" to decide how and where to showcase new products, Fetzer said.
To counter the drift, show organizers and exhibitors are rethinking formats and scrambling to associate with events and brands outside the staid universe of the combustion engine.
Next week's show will debut a New Mobility World forum with Google and Facebook as partners, while Mercedes hosts a conference under the banner of South by Southwest, the eclectic cultural gathering held in Texas. Rival BMW's program includes TED Talks-branded presentations.
Anxious not to be outdone, Paris show managers travelled to Las Vegas in January to discuss collaboration with CES, but came away empty-handed. "There are no discussions at this time for event expansion into Europe," a CES spokeswoman said.
"These are attempts to stay relevant in the public domain," said analyst Arndt Ellinghorst of Evercore ISI, a brokerage.
"The way people consume products and brands is changing," he said. "The days when it was enough to lure consumers to shows with half-dressed girls on car bonnets are long gone."
The modernization efforts have not prevented Tesla, Nissan or another half-dozen brands from quitting the car-show circuit.
For several years, Tesla attended the main European shows before opting out of both Geneva and Frankfurt this year - just as the North American launch of its $35,000 Model 3 makes waves.
"We look for events where automobiles might be less expected," a Tesla spokesman said, citing golf and boat shows as well as a European summer road trip with pop-up Tesla displays along the route. "We can reach a lot of people that way."
Nissan's decision to skip Frankfurt followed a "full review at global level of our event and show strategy to facilitate maximum brand visibility", the company said.
Reports of the car show's inevitable demise have been exaggerated, however.
As networking events, up to CEO level, they remain unmatched, while suppliers and new entrants are already filling gaps left by the patchier presence of some carmakers.
German industrial group Thyssenkrupp is returning after a decade's absence. "If the sector is going to change so dramatically we want to be there and show what we can do," said Karsten Kroos, head of the company's auto parts division.
Others skipping this show will be back. Instead of turning up every year, many carmakers simply want to opt in when they have something to announce.
"A car show is a marketing tool like any other, so it has to provide a return on investment," Peugeot brand chief Jean-Philippe Imparato told Reuters earlier this year. "But that doesn't mean we won't be in Frankfurt again before too long."