Technology invalidates the very idea of a zero-sum economy. If tomorrow we reach a breakthrough in fusion energy and are able to deliver all the energy the world needs at several order of magnitudes less cost, material, and space... well then we just gave a lot and took very little -- the pie grew -- the possibilities grew. It's not zero-sum.
Listen, simply decrying "zero-sum" doesn't make an argument anymore intelligent. You must seek to understand the concept and basis underlying the words you use. Only then does their true explanatory power become accessible.
[1]: https://en.wikipedia.org/wiki/Production%E2%80%93possibility...
As to how the zero sum game improves understanding: It's competition in a resource-constrained environment. I don't want to stick to strict economic theory and assume that wealth creation solves this issue. We've seen that people aren't satisfied by their phones, apps, food and entertainment choices, and high-tech gadgets that people in the past could only dream of. If anything it makes people want more. All the things mentioned, the house, the car, the kids, world travel, are goals people have that don't appear to have satisfying alternatives that don't use up a lot of resources or pollute the environment.