https://en.wikipedia.org/wiki/American_Battle_Monuments_Commission

not an answer on the monetary aspect. Good news is, the monetary aspect seems to be cared for.

Even better news, long since the war grave comissions of former enemies closely co-operate to keep up the memorials. There also seems to be a number of international agreements upon war graves.

There are no American war graves in Germany. US servicemen who died in Germany were not buried on the enemie's ground. The Netherlands were no enemy country, hence the US memorial there.

Edit I am in Zeeland/Netherlands for recreation sometimes, there is a small Commonwealth graveyard. Also very well cared for and a remarkable memorial.