I understand all the reasons why publishers use boxes that seem larger than they need to be, but I also understand that once a game is in your hands, you can do with it whatever you like (within the legal statutes of your town and country). Thus, I have now rightsized my copy of Berried Treasure, shrinking it to less than a quarter of its original size.
In the video below, I give a short update on the game itself — I've now played with five players, and the game is great at that count — then present an abbreviated run-through of how to resize a box, starting with general principles, then jumping from step to step in this project. The entire process took about an hour, and I was doing multiple takes of some video segments, shooting photos of the transformation, and otherwise interrupting myself, so you probably wouldn't need that much time to do something like this yourself.
Cutting up boxes might not be your thing, and if not, well, that's fine. You do whatever seems best with the games on your shelf. That said, if you ever throw out game boxes, e.g., expansion boxes because you packed the components into the box of the base game, maybe consider trying a project like this, transforming that expansion box into a card holder or bit bin. That box is garbage anyway, so you might as well experiment and see whether rightsizing might secretly be for you.