What is holding private label back in the United States and in emerging markets?

Private labels (PL), also known as store brands or private brands, account for hundreds of billions of dollars in consumer packaged goods sales every year. PLs build store loyalty, improve margins and have been a key factor in changing the balance of power between retailers and national brand (NB) manufacturers. Thus, retailers around the world have a stake in pushing their own store brands. Yet, while PLs enjoy great success in Western, and increasingly Central, Europe, their performance is much more muted in the world's largest market, the United States, and in emerging markets. Why is that the case? This thought piece provides a number of ideas, summarized in propositions that can be tested in future research.