I am really surprised that there isn't an established market for accounts yet. I think people are worried about the potential for fraud.
But, a HIVE account is like any other business and businesses can be developed and sold.
Some HIVE accounts are so tied in with a given persons identity that that will not want to sell. But, unfortunately, most people using HIVE are mortal. At some point users will pass away. HIVE is like any other personal asset. It will be inherited (or collected by the state for taxes).