At this week’s biennial Tokyo Motor Show, Toyota Motor Corp.’s booth didn’t feature any cars its customers can buy. Instead, the company showcased a mobile service that gives you a health checkup, with the slogan: “The star of the Toyota booth isn’t a car—the stars are people.”

There’s a good reason Toyota is shifting focus from individual cars: The global auto market is shrinking. World-wide sales fell in 2018, are expected to drop again this year, and Moody’s Investors Service projects another decline in 2020.

Some forecasters think this is mostly a temporary result of a troubled global environment. But structural headwinds may be more important. Rising trade barriers and stricter emissions controls are making cars more costly just as many countries’ markets have become saturated and alternatives like ride-sharing have sprung up. In the U.S., car sales peaked in 2016; in the European Union, in 2000; and in Japan, in 1990. Emerging markets were supposed to pick up the slack, but they too show signs of plateauing: Sales in the last 12 months are down 12% from mid-2018 in China and 14% in India. “Peak car,” loosely defined as a world with all the cars it needs, may be approaching.

This helps explain why car companies around the world are in turmoil despite low unemployment and healthy consumers. Germany’s Continental AG , one of the world’s largest auto-parts suppliers, announced Tuesday it was taking a €2.5 billion ($2.8 billion) write-down, warning it doesn’t expect global vehicle production to improve much in the next five years. General Motors Co. has endured a five-week strike to gain the flexibility to close plants, cut costs and invest more in electric and autonomous cars. In the second quarter, its sales in China, North America, Europe and South America all declined from a year earlier.