It seems to me that the question raised by the author of the topic is quite timely. How can you correlate a specific person with a specific private key? If someone spies on your notes in a notebook, then naturally he will become the owner of this private key in the same way as you yourself.
I got an idea. What if the binding of a private key to a specific person will carried out on the basis of some chip that identifies this person built into his body?) Then no one will doubt that only one person can own this private key. or as an option, a person, in addition to the private key itself, must have a certain second factor - like a yubikey or something else.
I understand - my thoughts are rather "raw", but maybe this will lead someone to another right idea.
I would say that your proposal is quite an efficient solution to the problem of proving ownership of private keys. However, as vapourminer correctly noted, for such a verification system to function as intended, we would have to deal with numerous third-parties, which in itself is unacceptable when it comes to decentralized systems such as Bitcoin. We would have to reveal our identities, sacrifice our right to privacy, entrust our lives to those who would be implanting the chips into our bodies. Besides, such chips might come with different backdoors and software for tracking your current location and history of purchases. That would give governments additional tools to control you.