Yes, but forced transfer or no, the money itself is not zero-sum. It’s the access to scarce resources (including time/labor) and the actual claims on those resources that are zero-sum. Money is a fungible proxy for these.

Technically, thanks to thermodynamics, the pie is constantly shrinking. We haven’t dug up or exploited all the useful stuff yet, so from our limited perspective there is still room to grow the pie. But we’re probably getting close to the limit, as the rate of consuming useful stuff is beginning to exceed the rate of digging it up or otherwise capturing it.