No, you made that up. There has been no decline.
https://www.statista.com/statistics/200002/international-car...
We’re going to add another 2 billion people and the world is getting richer. What do you think that will do the car sales?
https://www.statista.com/statistics/200002/international-car...
We’re going to add another 2 billion people and the world is getting richer. What do you think that will do the car sales?
[0] https://www.bloomberg.com/news/features/2019-02-28/this-is-w...
EDIT: More specifically on car sales, they do mention a decline in China: "IHS sees the biggest impact of mobility services coming in China. Auto sales there plunged 18 percent in January, an unprecedented seventh consecutive monthly decline, as commuters rapidly embraced ride-hailing."
“Researcher IHS Markit predicts the 100 million vehicle milestone will be surpassed in the next decade, but only because of growth in China, India, Russia, and other emerging markets”
China is already a much bigger car market than the US.
They are also experiencing a bit of an economic slowdown, probably cause by the trade war.
https://markets.businessinsider.com/amp/news/china-economic-...
We will have less cars, but each car will spend more time on the road. Currently most car are idle day and night in parking, being driven around 2 H/day (less for many many cars). Some families now are starting to use 1 car for the family + car sharing for everyone instead of 1 car per family member. If you combine that with self driving cars in around 10 years, the money will be made by the car makers making very reliable / sturdy cars for the driverless taxi companies.