The simple fact is that some food products are best sold canned for convenience, like kidney beans. Others are fine in polymer coated paper containers, like milk or fresh orange juice and yet others in plastic or glass bottles, refrigerated or not depending on the product. We see all kinds of dried fruit products. The use of nitrogen gas to eliminate oxygen during polymer packaging operations is great for avoiding food oxidation, discoloration and early spoilage. In short, the "shelf life" of products so packaged is vastly improved. Vacuum sealing is another way to protect food from bacteria, molds, insects and dirt and also oxidation and freezer burn, and it allows for attractive see through presentation. Flash freezing is yet another method used commercially to capture food freshness and texture that would be lost using conventional freezing methods. Irradiation is used, especially in poorer countries where refrigerators are a luxury, like Mexico, to preserve milk and meats.
All of the older and modern methods have their place. For the home chef it is important to learn which methods are right for which foods and how to do the processing successfully. We may not have flash freezing or irradiation devices at home yet but we pretty much have access to all the other essential pieces of equipment.