This is already the case for the majority of asset (stock or bond) wealth. The threshold to pull this off is way higher than simply getting a private key or hardware key device off someone. In the first case there are many controls to halt or prevent this sort of thing. In the second, if the perp gets the key, they've won.

You have some possible recourse if someone steals your securities without your authorization.

The reason why it's more appealing for criminals to do it with crypto is that claw-backs are essentially impossible.