Six walnuts have become the biggest brands in the walnut milk market. What is their competitiveness?

Six walnuts account for the vast majority of the walnut milk market. Now I want to buy walnut milk in the supermarket, most of which are six walnuts. However, there are other brands, such as Yili and Lulu, which entered the walnut milk market from 20 14, but their popularity is not very high. The market share of Yili walnut milk is less than 10%, which is far from the six walnuts.