as the article points out the game was in particular desgigned to show the economic effects of private land rent, hence the original title 'the landlord's game', and that is in fact a zero sum game as they aren't making any more of it.

And in particular on tech websites like these people vastly overstate how non 'zero-sum' economic activity actually is mostly because tech has been in a bubble of highly anomalous growth. (A lot of it ironically arguably not real productivity growth but rent collection through platforms and market power).

In many ways the tech startups of today look more like digital landlords than innovators whose disruption is primarily taking over the market from a host of competitors rather than improving process efficiency. If we were living in Fordist times and the assembly line and other innovations delivered 6-7% growth annually, then we could rave on about non-zero sum economies. Total factor productivity growth these days is relatively non-existent.