The binary part is to make it easier to understand.
This is not about new cars, this is about second hand cars. And even if it was about new cars, you wouldn't know for another 5 years if the new car you bought was bad quality or not. (assuming you can't rely on the reputation of the car maker)
The problem with second hand cars is that I sell my car every 5 years, so I basically don't have any reputation. And you don't know how well I maintained my car. All you can see it that it looks shiny.
You can't let me test it, because you don't know if I got the certificate from a genuine unbiased party or from my brother in law. So if you want to test the quality of the car, it's going to cost you. Plus I'm not even sure if you can let it be test cheaply. I can paint over rust, roll back the odometer and do some quick fixes to make the car run smoothly, for now. Are you going to have the car taken apart in the test?
The problem now becomes that I know the quality of the car and you don't. The uncertainty is going to drive the price down. Sellers of good cars will hesitate to compete, because it's impossible for them to ask for a premium price. I'll probably keep the car longer (it's still good, why not) or sell it to a friend, who can rely on my reputation. Now the average quality of cars on the open market goes down, which drives the price down even further, which makes it even less likely a good car will end up on the open market, which drives the price even further down, etc.