Sure, but now we're back to the current US system, where you have to multiply or divide by the amount in the container (either servings per container, or grams per container) to make sense of the measurement.
Standardizing to 100g doesn't actually make it easier to compare foods, because I don't know how 100g of popcorn compares to 100g of chocolate or 100g of soup. It just doesn't mean anything to me.
From my experience, it does make it easier if you need to compare similar foods.
For example, I want to buy a yogurt with highest amount of protein. Serving sizes may vary between 150 and to 500gr. With standardized labels it is very easy task.
In my country we have calories listed for both 100g/container and nutrients are always listed for 100g and sometimes for full contaiber. I almost always use 100g part.
In the US, serving sizes are generally standardized per type of food, so two quart containers of yogurt will always have the same serving size in the nutrition facts.
