I also think about those people sometimes that how would they feel right now when they see the price of bitcoin when they used multiple bitcoins for buying a pizza or they just left them idle in their wallets and never used them until now, they would have been rich by now if they have kept them safe.
A lot of the early users were careless about their coins. Some of them forgot to keep their private keys securely. Some of them lost their coins in scams and ponzi schemes. And there were a few who lost their coins in wallet robberies.