Let's assume, that the day already came, when emission of bitcoins completed, and we have the 21 millions of bitcoins. Let's say it happen that all these Bitcoins at one moment became the property of one person (for example because of the vulnerability of the system), which says that will not make any transaction and produces all kinds of steps to achieve this target(the deletion of the account or something else). So here is the question - what will be happen if 21 million of bitcoins become the property of one?