Why good used cars quietly leave the market.
George Akerlof showed in 1970 that when only the seller knows the quality, buyers pay just an average price. For good goods that is too little, so they withdraw – and the average sinks further. This adverse selection can dry a market out entirely.
Useful: The remedy is signalling: warranties, inspection reports, certificates. They cost money, which is exactly why they work.
Source: de.wikipedia.org