The hardest thing is logistics: delivering product orders on time as a small brand which outsources manufacturing is really hard. Big retailers, like Nordstrom or Macy's will give you a window of a week (maximum) and will not accept your orders if it goes over. Conversely, they also have set packaging and other compliance related requirements which will increase the cost / item. In particular they have these ERP systems that small brands cannot afford. Smaller brands end up outsourcing being plugged into their ERP systems as well which will also increase the cost of the article.