Going to zero is one potential outcome. Equally plausible is it goes up 10% in a relatively quick battle or diplomatic outcome which ends the geopolitical uncertainty.
This is the beauty of Polymarket. Then bet on it. There are so many more outcomes possible to this conflict than what you see reported in the media. Don't be so reductive.
When people do this kind of predictions, they often driven by emotional reaction. Best thing to switch actual evaluation on certain hypothesis is to make actual risks cost something.