I think if anyone were to try to actually do this then the value of bitcon would essentially become worthless. BTC gets it's value from two sources, as being a unit of trade and from the security of the network. If you hold/control all of the BTC then there is obviously no trade happening (unless you trade with yourself) so it would receive no value from this. It would also mean that the network would not be secure anymore as miners would have no incentive to mine as they (at this point) would be receiving all of their compensation from TX fees, but if one person controls all of the BTC then he would obviously not be sending BTC to his various addresses (he would have no reason to) therefore there would be on TX fees to be had.