Not always the case recently. Shopping this year I found that <2 year old used cars were often more expensive than new cars due to lack of dealer incentives and concessions on financing. A similar dynamic is emerging for houses [1] as homebuilders have more reasons to sell their inventory than existing homeowners do.
Have you tried shopping for a car in the last 3 years? Because if you had I’d expect you wouldn’t be making this statement. In my area many used models are MORE expensive than new ones due to onerous wait times and dealer shenanigans.
Even that is debatable. My newest car is a 2006 model year. I bought it a couple of years ago. It's perfectly reliable, I paid $4,000 for it.
How exactly are the cars becoming “certified used” if 0% of people are buying them new..?
Corporate fleet vehicles (rental cars, 'company cars') are the main source.