Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

How can it be possible that only ~10% of options expire worthless, and only ~10% are exercised?
You gave your own answer - the 80% is positions, not contracts. Most actors on the option market have no interest in the underlying asset. They want "just" exposure to its price movement. It makes more sense to close your position than to be handed over bushels of wheat or whatever.