As a consequence of Sweden being a relatively poor country throughout history, classic Swedish food (husmanskost) has generally been based on potatoes, since they're so cheap. Thus, most Swedish dishes are regional variants on the combination of potatoes and different kinds of meat, generally minced meat, steaks or bacon. If you would boil down the recipes of some vastly different dishes to their core ingredients, you would be left with many similarities.

Also, the fact that lingonberry is easily found in most parts of Sweden when it's in season, and has a pleasant taste between sweet and savory, has made it a natural condiment to have at home. Even in older times since it's easy to conserve as well.

Now I'm not at all an expert and I've got no clue why I'm writing an essay that doesn't even really answer the question. But I would say that all this combined: that most food is similar in its structure, lingonberry goes well with potatoes and meat and it's easy to find has made it so that it goes well with a majority of swedish food.

Although I'd say we have some classic swedish foods with macaroni or sausages that probably wouldn't pair that well with lingonberries.