"The economy" may or may not be a zero-sum game. It really depends on what scale it's being evaluated. Cosmically speaking, the first law of thermodynamics rules out perpetual motion machines. But even if we assume that at a more mundane scale the economy is a non zero-sum game that doesn't mean that none of its component parts may be zero-sum games. That would be a fallacy of division.
"...it is fallacious to conclude (distributively) that each or every member of a class has a property from the premise that the class (collectively) has that property. Thus, the whole class collectively may be [non zero-sum], but a part of that class may not necessarily have that property -- i.e., may not be [non zero- sum]."