I'd love to see a market for selling accounts develop. But since you can't transfer SP, then it means you really can't sell them in a secure way. So no such liquid market will develop. You basically have to trust someone to let them have your account and change the password. Someone has to go first and take all the risk.
Curation income is not worth anyone's time at only 3.875% of their holdings per year.
That's what using a trusted escrow is for. Of course, the person doing the escrow could go rogue and take everything from both parties.
Edit:There still seems to be an option to recover a stolen account. So, only a fool would buy an account. The seller could initiate this process after collecting the funds.