I think my point is that Bitcoin isn’t different (in some aspects) compared to other asset.
If a company accidentally sent a bundle of cash via registered mail to the wrong person, the recipient (if known) would probably have to return that cash after a court ruling.
If Coinbase made an erroneous transfer of BTC to one of their customers (whose identities they know), the recipient would probably have to return the bitcoins after a court ruling.
If the recipient of the mailed cash is unknown, or the person associated with the receiving wallet is unknown, then the court could obviously do nothing. But that inability is a function of the knowledge about the parties involved, not of the underlying technologies.
Bitcoin obviously makes it much easier to be unknown to the judicial system. But in my view, for it to be completely not-theft, the recipient should be able to announce publicly what he has done without fear of repercussions.
Similar to how e.g digging up historical artifacts in some jurisdictions is a legal way to gain ownership of something that previously had a different owner.