There was a deal of kit left in the Canal Zone. Likewise when the US had a falling out with Nasser, their ex-new best friend, they just abandoned all their heavy construction plant. It was still there 15 years later, untouched and unuseable.
Cheaper to dump than recover. Besides, if you hand over 1200 clap out vehicles you can probably sell them spares and maintenance. Bring them home and to the transport costs you pay for that maintenance.