The explicit invocation of the concept "zero-sum" is avoided because it's a lightning rod for criticism, where someone will inevitably chime in to point out the

The explicit invocation of the concept "zero-sum" is avoided because it's a lightning rod for criticism, where someone will inevitably chime in to point out the realization of absolute gains of utility among the losers also; specifically, that important metrics like living standards have been improving for wide swaths of the population, even those whose share of wealth declined over time. And therein lies the disconnect: both can be true, because one of them is a tautology; and it just so happens that relative disparities in wealth among the pool of people in market for a service will cause the competition to attain some elements of an auction, and cause the poorer parties to lose out.