Actually the Marshall Plan was good economics. You have an economy on a war footing , going flat out twenty four hours a day. Full employment good wages. Into this you will be bringing a large number of men and women demobilised. They now need jobs. Add to this a lot of military surplus vehicles and other equipment, if you ship it back and sell in your economy, whose going to buy new if they can get stuff cheap?
On the other hand, you have the kit, give it away to former allies whose industries are in tatters. Result they are very grateful, and have to come to you for spares. Also as happned in Britian, heavy haulage equipment in the form of T's and Pacifics could be bought for about £200 as comapred to about £1500 for the equivalent Scammel, a technically inferior vehicle, not to mention the waiting list.
The overall result was a continuation of the US stated aim to seperate the European countries from their empires, especially UK from India. No matter what the declared reasons, wars are 'Economics by other means'.