Are wallets even completely bought themselves? Because how can one buy a wallet from another person without paying the person, which can't be seen as a complete legal deal? Since wallet phrases and keys can't be changed, the old key will continue to be the right key to the wallet, which the old owner will still have access to. So if you have purchased any wallet from anyone, the person is still likely to move out your assets when they notice a balance change.

So I don't think anyone who knows how the blockchain works will actually want to buy any crypto wallet from anyone, no matter who the person turns out to be. Because security is not always guaranteed.