Standard of living has improved generally over time, but day by day the world is a zero-sum game.
I'm not entirely certain what you mean by this question. the homeless person could even be worse off today than they were fifty years ago, and the economy could simultaneously be positive-sum. suppose you have an economy with two people that each start with $100k. if after 10 years, one person has $500k and the other has nothing, this is a positive-sum game because the total gains exceed the total losses. positive sum does not imply that everyone, or even most people, will become wealthier over time.
> Standard of living has improved generally over time, but day by day the world is a zero-sum game.
if you pick an infinitesimally small window of time where nothing can be produced, then sure, I guess you could say any changes in wealth would have to be zero-sum (assuming you could somehow transfer wealth instantly). I don't really think this is a useful analysis though. over the course of a whole day, the economy could be positive, negative, or zero sum. it depends on how much total wealth was created and destroyed on that day. even in an hour, I could create something of value that didn't exist before, or an explosion could go off in a port causing billions of dollars worth of damage.