Repackaging shelf-stable products
Exposure to germs is the problem, once you open these they are exposed and the clock starts. If you vacuum seal you are vacuum sealing the germs in with the food, and not taking steps to kill the pathogens. Pouring into a sterilized container again just puts contaminated food into an uncontaminated container. 

The only way to make them shelf stable again would be to process them. You could vacuum seal and then pasteurize the food inside for example, or re-can and pressure-cook. This takes a lot of time and energy, and each time you do it you lose quality.