True, but I think werber was referring to grocery stores (or the like).
But that's hardly something unique to Germany then. Off the top of my head, the Netherlands, France, Belgium, Spain, UK, Germany, Denmark, and Finland all have their own set of national grocery store chains, with only very little cross-border movement (Aldi and Lidl are the big exceptions).
Poland seems exceptional in this regard - there are local chains here, but they are heavily outmassed by foreign brands, ranging from German LIDL, through Portuguese Jeronimo Martins to French and British franchises. That's probably because of a skewed tax policy favouring foreign companies over locals, which I have a hard time understanding.