That's not a given. There are multiple historical periods where wealth was effectively zero-sum. These periods often aligned with strong income inequality and an inability for individuals to purchase productive assets e.g. Feudal Europe, and Tzarist Russia.

On an individual basis there are multiple portions of the economy for which wealth could be modeled or interpreted as a zero-sum game. Examples include landlord/renter relationships in high rent burden environments, or other segments where an individual is unlikely to ever be able to afford a "share of future economic growth" in order to fund retirement etc.