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.
Yes, of course, if we were forced to use this kind of implantable microchips, then naturally this, too, theoretically could give rise to another vector of attacks from hackers, and there is no doubt that government intelligence agencies would also take advantage of these opportunities. But now this attacks would be directed not at the user of the wallet or his laptop. Now hackers would attack directly the manufacturers of these microchips.
But despite this, I still like this idea, because in this way it would very likely solve the problem of identifying the owner of the private key.
And, yes, I perfectly understand that if everyone began to use such identifying microchips, then, in addition to hacker attacks, this could also lead to even more terrible things - for example, if the chip was located in the hand, or somewhere under the human skin, and if it was a certain public figure, then for sure there would be some completely reckless personalities who would not have disdained by committing physical attacks on carriers of such chips in order to extract them from bodies.
And if such wallets will contain millions or tens of millions of dollars, then, I'm sure that after some time it would become our everyday reality.
The movie Looper with Bruce Willis comes to mind for some reason. There, a plot was played up in which people were hunted in an unusual way, because it was impossible to kill such people with ordinary means precisely because of various kinds of identifiers that were used in the future on our planet.
But despite these new vectors of dangers that may take place, I still think that society will gradually move in this direction - the identification of everything and everyone on this planet.
In the meantime, for any rich guy, one single rule is still relevant: "If you want to stay rich, keep your private key a secret from everyone."
