Can someone explain (in term of wealth taxation) the statement by Thomas Pikkety (2014: 571) wealth ‘accumulated in the past grows more rapidly than…

Can someone explain (in term of wealth taxation) the statement by Thomas Pikkety (2014: 571) wealth ‘accumulated in the past grows more rapidly

than output and wages’. This imply that governments may have to take a fresh look at

wealth taxes to promote equity. Does this statement make sense? advantage and disadvantage?