Brian Armstrong was on Tyler Cowen and Tyler asked him if bitcoin was a zero sum game, in a round about way:
COWEN: I’ve seen estimates that about 20 percent of bitcoin has been lost, or people don’t have their passwords, or it’s somehow abandoned or whatever. Let’s say that 20 percent were found. Those people would be better off, right? They’d have more wealth. Who is then worse off?
ARMSTRONG: Yes, I suppose you have dilution, and you have inflation if you’re increasing the money supply somehow like that.
COWEN: Then if we ask the general question that the social value of bitcoin — bitcoin in general — again, clearly a benefit to the people who bought at low prices. They in essence found bitcoin. But if someone else in the system is losing an equal amount, why think that the social value of bitcoin is positive?
ARMSTRONG: Who’s losing the equivalent amount in this case, just so I understand?
COWEN: I don’t know exactly who, but someone else has less purchasing power, right? Bitcoin isn’t apples. You can’t eat it for lunch.
ARMSTRONG: It’s not clear to me that bitcoin is a zero-sum game.
COWEN: But what is that? When do I get my apples, so to speak? Where do they come from?
ARMSTRONG: Well, anybody can participate of course. I think, now, about probably 10 percent of Americans and maybe 60 or 70 million people globally have crypto, at least. So it’s been growing a lot.
Brian didn't seem to understand the question and it left me a bit unimpressed.
https://conversationswithtyler.com/episodes/brian-armstrong/