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.
I don't think that they would be careless about their coins as after all its a money and everyone will keep their money safe in their hands, if they have lost in ponzi schemes or gambling then that's a different thing but people who had great vision would surely have kept their coins safe and already would have get rich with it.
I remember that there is a thread that asking for buying pizza to deliver in his house and offer 10,000 bitcoin i forgot the thread but the man who got 10,000 btc is lucky if he is holding it until now because the price is increased..
So keeping it safe is always good but if you don't have knowledge for securing your computer and wallet maybe it can be gone forgot or hack by thieves. If i am one of the old user before i keep collecting bitcoin and maybe i am mining bitcoins too.. and hold even 50k amount of bitcoin and holding until now.. but it is just a dream right now because i do not try bitcoin when i was heard it before..