John only inherited a part of the Butes' Glamorgan estates, and in the first decades of the 20th century he sold off much of the remaining assets around Cardiff, including the coal mines, docks and railway companies, with the bulk of the land interests being finally sold off or nationalised in 1938.
约翰只继承了部分格拉摩根的家产，在20世纪的第一个十年里他卖掉了许多剩下的加的夫附近的财产，包括煤矿、码头和铁路公司，最后家族所有的地在1938年都被卖掉或者国有化了。