That's the point. Forcing them to move them would produce proof that the coins are active. And I would argue that to make supply and demand work (correctly) you need to know the supply.
All you need to know for the 'supply' side of things, is to check the market depth on the exchanges. That is your 'supply'.
Supply isn't all of the coin that exists, it is all of the coin that people have put up to sell.
Exchange rate also isn't determined by how many coin are in existence.
=squeak=