That simply isn't true, it is a mathematical fallacy people often fall into when dealing with infinity.

To take an extreme example, imagine that ALL bitcoins have already been mined, and there are no more bitcoins to be found. Then imagine that they start blacklisting bitcoins at an incredible rate: HALF of all bitcoins in existence are blacklisted each year. Remembering that it is possible to subdivide bitcoins (and arbitrarily far, given minor changes to the protocol), in what year will there be no coins left?