New cars do depreciate, but how much is largely dependent on the car. Some come very close to long-term deprecation rate. Luxury cars depreciate most, exotic cars with low mileage and some Toyotas depreciate least.

However, buying used isn't always the best choice. First, "nobody washes a rental car" and most people treat leases as rentals. Second, you will pay dealership markup, so above fair market value, to buy such car. This is even before "Certified Used" scams. Plus, with many people going for 8 year "mortgage" on cars, off the lease 2-3 year old cars are rare.  Third, you will not be eligible for manufacturer rebates when buying used.

As such, I believe the best value is to buy a new car that tends to hold value (e.g. Subaru, Toyota) at the year end when most manufacturers offer discounts to move last-year models off the lot. If there is a redesigned new incoming model you will get even bigger discount. Then you hold on to this car for 6-8 years and then privately sell it.