not necessarily, in the future we could fork bitcoin and adding something to restore those coins, i'm thinking what would happen in this case, the price will decrease because more coins will be accessible or it will remain the same/increase? and who will be the owner of those coins?(i'm theorizing that the original owner has no track anymore of his lost coins)
I really hope that never happens. There's no way of telling whether coins are just parked. I wouldn't be best pleased if my coins suddenly disappeared from my grasp because a bunch of strangers decided they might be 'lost'.
You can say it, for example you could trace the transaction of similar addresses or from where he got inputs/ outputs, and correlate with those.
If he has a deterministic wallet of course.
