I am sure Kevin's tongue was lodged firmly in his cheek when he suggested manufacturers must be doing well as those who supplied supermarkets enjoyed operating profits "more than double" those of their customers.
Given the competitive state of the market, some, particularly in own label, would dispute that statement. The real issue is that manufacturers and retailers are very different businesses built around different models with different financial requirements.
Successful retailers sell products quickly and in high volumes; successful manufacturers develop and supply these products. That requires constant innovation, none of which comes cheap. That is why manufacturers need to generate a decent margin on the products they sell so they can keep investing in their businesses for tomorrow.