No. Neither side wants the world to crumble tomorrow (I hope). Therefore it is not zero sum

Similarly, energy from the sun isn't going to happen or not, so there's plenty of wealth being left on the table so that entropy isn't a good argument for zero sum

"zero sum" is a hateful philosophy. It means I'd kill your children because if that's terrible for you it must be oppositely great for me

aside: realized that "competing for survival where only one can get out" isn't even enough to be zero-sum if both can die. Here's a "Gladiator's Dilemma": if both choose to fight, both die. If neither chooses to fight, both die. If only one chooses to fight, the other dies. This game is not zero-sum, as neither side necessarily gains anything by the other's death