the car color thing may be real, but also it may be that people went overboard with color because they could, and then color got boring.

For the percent of colors in photos, i m not sure. Older technologies oversaturated colors and probably underrepresented greys (or turned them to red/green) , but maybe newer photo technologies allowed more blues and greys.

The cinema thing is real and very annoying to the point where i have to oversaturate all my screens in order to stop seeing actors' faces as corpses.