In 'profits for the supermarket are not strong enough' one can add that these matters always involve negotiation.
The supermarket chains love to screw suppliers and typically negotiate shelf placement fees (payable by manufacturers) unless the world has drastically changed. Look at a company such as PTL (doing well) to see its massive expenditure on promotional activity, much of which is allegedly this, rather than 'direct to consumer' Facebook/Google/Instagram/Snapchat/traditional TV/newspaper/billboard/influencers' advertising.