That's not always the way it works.

As a consumer, you might be able to justify $200 on something for X purpose. But if you see another device that can also do X AND Y, you might be able to justify spending $300. That doesn't mean you could justify spending $300 on something that only did X, and you might not find anything good that only did Y for $100.

i.e. it's not necessarily zero-sum.