It does somewhat prove though that lost Bitcoin in this type of situation is actually harder to return to its original owner than if it was fiat.
How so? If someone loses their paper wallet, you can open threads in Internet boards. Or send some funds there with a message, describing where and how you found it. There's absolutely no manner to verify who's the one who lost their cash on the street, unless the physical wallet with the identity is also dropped.
I watched a movie where a certain rich man's son was kidnapped, and when the news was flash on TV stations about the incident, this rich man started receiving messages from multiple groups and persons demanding for a ransom claiming to have kidnapped the man's son whereas the actual kidnappers haven't contacted the man for any request yet. The man got confused not knowing who could be the real kidnapper. In same vein, should the founder of the wallet decides to open a thread on any internet or cryptocurrency boards/forum and got to entertain multiple persons claiming to be owners to the missing wallet and especially in a situation where there's no means of identification that was found in the physical wallet in which the paper wallet was found in. This subject now becomes rigorous and disturbing to knowing who the real owner is. Sometimes the real owner may not be using any of the socials, maybe!