No coins are forever lost. They will all eventually move to another address in the Blockchain. It's just a question of when not if. There are people working on it day and night, using more and more advanced equipment.
This is not true, there are some Bitcoin that are actually lost forever and would
remain in their respective addresses because the owners don't have access to the private keys, probably loss or misplaced and the coins will remain unspent until when the would be to find the keys or remain there forever.
The private keys, will be found by someone else and the coins will be moved.