Economics is not physics. It has no laws. And the field could not exist if it were zero-sum.

Edit: I should clarify that economics does not have laws in the same way physics does. The ‘law of diminishing returns’, for example, is more of a trend or generalization than an absolute, and is frequently violated in a way that gravity is not.

Economics is also still not a well understood field. There may be government policies with unexpected effects due to that incomplete understanding. We have seen this many times.