Okay, the first question has to do with stale bitcoins. Say people lose their private keys. Over time it just keeps building, and a large portion of the 21mm bitcoins are immobilized. What happens?
The same scenario can occur for a different reason, say people start putting bitcoins in their IRAs and there millions of bitcoins held immobile. Also, how do I know that in 20 years they still will be good. Maybe the network truncates the transaction log and my part falls off.