21M supply is same with the current supply even though some of them are lost in the wild. Logically this is a broad discussion.
Nothing ever gets lost. People are even talking that quantum computers will hack bitcoin network and who cares about lost bitcoins, they should be easy to restore.
Its actually lost. How can you say it can be restored if that's easy to retrieved many already try out to recover those who sent on a wrong address. That will defied transparency if this can be work out.
I dont think those wronfully sent will affect its value rather it could boost is demand. Those are still part of circulation that laid waste but still it just dormant.