We are able to use existing resources more and more efficiently. This is why the global wealth per person is higher than it was in say Roman times, despite the global population being orders of magnitudes higher
As a result of the above, the value of a natural resource changes over time. For example, natural resources used in electronics and batteries are relatively more expensive now than they were 100 years ago.
So, you can be technically correct by saying that wealth is zero-sum, but that's pretty much the same thing as saying "the world's 'wealth' traded for natural resources sums up to 100% of all natural resources"