Yes, a higher base of mature stores will impact the growth rate. However, it should do an earnings growth of 20% -25%. Every time it adds a new store, the unit economics improves and it has recently entered some new clusters.
The reason for the margins that dmart has are structural in nature rather than market led. Low debt, low rent etc are all conscious choices and the quality of margins is much superior so I am not convinced about peak margins. They can improve further is my view and could be wrong about it as well.
The other aspect of dmart is that it pays its suppliers super fast. In essence it funds the working capital needs of its suppliers. If you are a supplier to dmart and it constitutes a major part of your business then you are likely to have a low receivable period and are cash flow positive. This would enable you to grow quickly. The supply chain of dmart is very stable for this reason. The importance of a strong supply chain cannot be highlighted enough in retail. In many cases the main source of working capital financing is not a bank but dmart.