Headlight Epidemic!

Strange sort of phenomena regarding car headlights around us at the moment. There just seem to be so many cars driving around with a headlight not working! We counted eight tonight within a five mile journey, plus two others who had simply forgotten to turn them on!

Why? I wondered if the headlight units on modern cars were so expensive that owners couldn't afford to replace them. (These are not old bangers, some are at the luxury end such as RR Evoque!) OH thinks owners are just leaving things until next service, and of course some drivers are so bad they probably haven't noticed!

Any other ideas?