In the US the average length of car ownership for new cars is 6.5 years [1], so it does matter what your car is worth after this time. Not sure if it amounts to ca. 6,000 USD per year, tho. That's a lot of depreciation.
The type of person who buys a brand new car probably likes a brand new car (new features, status, reliability, etc) and that doesn't change after a handful of years. Or the other way around, the type of person who wants to maintain an older vehicle is probably not the type of person who will buy a brand new car.
Obviously there are exceptions, but the used car market is much larger than the new car market so most are selling.
[1]: https://www.statista.com/statistics/581017/average-length-of...