Wouldn't lost bitcoin be one of the inherent faults with the bitcoin system? It seems inevitable that a huge percentage of bitcoin will eventually be locked/unusable as people continue to lose their wallets or passwords, etc. What happens when 25% or 50% of bitcoin is "lost"? Of course, maybe by then, we'll have already moved on to a "better" cryptocurrency.
Satoshi said this is no problem, as lost coins just count as microscopic donations to all other account holders.