Plus retail has its costs too, markup for vinyl used to be around 50%, plus VAT. So you'd buy the 12" from the distributor at 5–6 € net and sell it for 9–10 € incl. tax (numbers from 10 years ago in Germany, probably haven't changed all that much). Owing to low volume (you can only move so many units), running a record store inevitably leads to self-exploitation.