I'm finding the "positive sum" language around coins really misleading.

It's literally the opposite. If the way users make money from their content is when other users buy it, it's literally zero sum, financially. Not everyone can be making money, unless external capital is being injected from a another source (which is losing money).

I think this misses the bigger picture. 

if you treat coins purely as a closed system with buyers and sellers, it looks zero sum. but that ignores the fact that attention and discovery are not fixed resources.

the “positive sum” comes not from everyone making magic internet money, but from the system enabling value to emerge where there was none before.

leads to better discovery, better content, and more people opting in, that is net positive. also remember that money is infinite, and if not injected here, its injected elsewhere.

check the Collectable on FC. Is there really "better discovery" there? I'd argue the most "valuable" casts are those that already get the most attention on the network

only way for coins to not be zero-sum is if value is created in the system and demand flows toward that value. Speculative value isn't real value