If you consider the progression of a Food Bank, it most likely started out with dumpster diving connoisseurs who got more sophisticated and professional with their discipline. Maybe they spyed on the targeted grocery store and learned when certain foods were scheduled to be thrown in the trash. It could have gotten to the point that they negotiated a scheduled pickup time and learned to work with each other on that.
The Food Banks had to start somewhere. That somewhere starts with a need from a certain class of people who are motivated to improve their lives. Some of them also are interested in helping others also improving their lives.
The Trickle Down theory works in that the people with money buy the food they want at the grocery store, and the scraps that have to be thrown away will instead go to the Food Banks or dumpster divers.
I think the grocery stores are going to be very reasonable about giving food to the local Food Bank. It is far safer and cleaner to give the extra food to volunteers rather than risk having people crawl through their trash out back and making a mess like a mangy bear.
The people who are more likely to dive in dumpsters are probably from small towns that do not have a Food Bank program. There is no structure or location to collect the food and it is more of an “every man for himself” mentality with distribution. When volunteers can congregate and work together, only then can the Food Bank become more of an institution to be shared with the people.