I disagree with that because most people buying a new car are going to be holding on to it for a number of years. A car is not meant to be an investment (unless you are collecting antiques) so it is irrelevant how much "value" it loses when you drive it off the lot.
Buying a used car might be cheaper up front but it carries the risk of major repairs because you will never know how the previous owner maintained it. Plus, unless the previous owner was a neat freak, you are going to be dealing with somebody else's food crumbs in every nook and cranny, stains on the interior carpets, etc. Most people are slobs when it comes to their cars. I absolutely forbid anybody to eat food in my car and get it professionally detailed every spring so it keeps looking brand new year after year.
It's true that more people are holding onto their cars now longer than ever before however many of the folks I know are still trading in/trading up every 2, occasionally 3 years. Every time they do, they take a financial bath.
For those of us that drive 'em until the wheels fall off, you're right.