But isn't there a limited coins at the end?!! there should be a xx time of idl for coins in wallets or inactive wallets :( this will suck if people keep loosing coin, it will crash the system at one point! :-\
There is no other way. No one should ever take control of other people's coins even if they are idle.
No harm will be done to the system. Bitcoins are pretty divisible and everything will work fine even if more than 99% of all the coins are lost.