From what I understood from my late and dearly departed dad, a WWII vet who served in the SPT, the US Army abandoned a lot of jeeps and other vehicles on some South Pacific islands near and at the end of the war as it was just not economical to ship them all back home. Of course those islands had been completely liberated and secured from the Japanese and were not likely to fall into enemy hands.
My dad also told me he saw pallets of bags of sugar and flour and other food supplies and even barrels gasoline being dumped into the Pacific Ocean from the sides of Naval supply ships as they had more than they needed and many of the supply depots were full. But it did pi$$ off my dad when he read letters from home from his family about ration coupons and shortages. But then again, shipping these excess supplies back home would not only be not economical or feasible, but some items would spoil or be unusable even if they were shipped back to the US.
In 1948 the USMC swept many of these islands for usable salvage equipment.
Under MacArthur's orders in 1949, 8th Army in Korea did the same.
Most of the vehicles used to fight the first year in Korea were those vehicles rebuilt by Japanese workers under contract to the US Army because anything new built in the USA after Inchon was being sent to Germany to rebuild the US Army there.