That makes sense, and I was thinking along similar lines in terms of the cost of food, but it is also something that has to be driven by consumers. Government regulation may help, but it may not.
Getting ride of single serving packaging cannot really be done through the initiative of individual businesses. Consumers will simply switch to products providing single serving packages if that is what they desire. What has to be changed is the desire. You also have to consider that there are cases when small package sizes are legitimate, such as when someone uses very little of a product.
Regulation may not solve the problem either. Some people simply prefer single use packaging over cleaning and reusing smaller containers. Consider something like school lunches. When schools ask families to pack lunches using reusable containers, there is often a backlash and a few who simply don't understand the concept of reusable packaging. Quite often, things get sent in baggies or plastic wrap or inexpensive containers that are only used a handful of times before being tossed. This is ignoring the world of adult lunches, where adults often do the same or worse (e.g. ordering food in disposable packaging).
As simple as the solutions may sound, getting people to go along with it is a difficult problem.