FRANKFURT — It’s a scary time to be in the car business.

The internal combustion engine is under attack from electric challengers. Car ownership is becoming optional in the age of Uber. Regulators around the world are fining companies that don’t do enough to cut carbon dioxide emissions, even as buyers demand gas-guzzling S.U.V.s. Global auto sales are slipping for the first time in a decade, disrupted by President Trump’s escalating trade war.

With so much bearing down on them simultaneously, it’s little wonder that companies like Fiat Chrysler and Renault were considering joining forces to survive. Fiat Chrysler’s decision Wednesday night to withdraw its offer to merge with Renault, citing government demands in France, was another reminder that change is complicated for traditional carmakers.

The aborted proposal to create the world’s third-largest automaker was a response to the disruption threatening an industry that accounts for many of the world’s factory jobs and is crucial to the economic fortunes of the United States, Japan and Europe.

[Fiat Chrysler and PSA, the parent company of Peugeot, announce a merger.]

New technology has unraveled industries like entertainment, media, telecommunications and retailing, weakening the job security of millions of workers and helping to fuel populism. Carmakers, clearly, are next.