The matches

Poland before 2WW.
Two friends, Jan and Saul, have a discussion.
Jan says:
- I don't understand why the Jewish shops have more customers and a higher turnover than the Polish ones.
Saul replies:
I will explain it to you using a practical example. First, we will go to a Polish shop and then to a Jewish one and try to buy the same goods. Then you will understand.
They enter a Polish shop, and Saul asks for a box of matches. The salesperson gives him the box. Saul opens it, and as usual, the matches are lying on the side of the label.
Saul says to the salesperson:
- I would like to buy a box of matches where the matches are lying on the opposite side.
The salesperson opens several other boxes, but the matches are on the same side, on the side of the label. Saul insists:
- But I would like such matches.
The salesperson says:
- I am very sorry, but we do not have such matches.
The friends leave the shop and go to the Jewish shop, where the history repeats itself. The matches are lying on the label side.
Saul repeats:
- But I would buy the box with the matches on the opposite side.
The Jewish salesman says, "Wait a minute," and goes to the store backroom.
After two minutes, he comes back and hands Saul the matches. And they are on the opposite side!
After buying a box of matches, the guys leave the store, and Saul says to Jan:
- Now you have seen it with your own eyes!
Jan replies:
- Yes, I did. But maybe the guy in the Polish store didn't have any matches like that?