Turn everything around and ask the same questions of bitcoin. What happens when people stop buying bitcoin with fiat? It's a joke to consider miners churning out arbitrary computations the creation of some "real value" and disregard the value that the entire steem community has identified in users' writing.
What's more valuable, content that people enjoy or wasted cpu cycles?
It's all an illusion...
Heheh. I was thinking the exact same thing. "Wait, is this guy arguing bitcoin is a ponzi scheme?"