Both depend on each other. Both are nothing in business without the other part. As much as a business depends on their customers. However customers only depend on suppliers if they supply something that truly is needed in life. Find true needs of your environment and meet these needs in a honest way of doing business, rather than first producing products and then trying to create an need.
True needs require no or little advertisement.
Artificial needs require tremendous investment for advertisement and may find a strong competition. Here an example out of the recreational industry. People are looking for more recreational activities providing them with fun and enjoyment. Having fun is a basic human need. They may need any kind recreation or anything else that provides them with fun and enjoyment.