This is not groundbreaking, but it could solve some of the 1) travelling with only hand luggage problems 2) food getting wasted.
The idea is that all brands (or one company specialises in making legal copies...) should offer not only the standard packages à 300 and 500 ml, but also containers with 100 ml or less.
Particularly interesting to examine when it comes to less frequently used ingredients - green curry paste, jam, red pesto (or, beauty creams with particular smells). If there is less of it, we can transport it even when flying and more easily gift them to our friends and families. If there is less of it we also can use it all up easier. Do you find the 100 ml too small? Then you can always buy five units. Do you find it more expensive per liter? Well, still made cheaper than throwing the other 200 ml away.