I think I was listening to Dan Carlin say this or something similar. From my limited understanding, it was basically the major part the wealth of 4 world empires (British, French, Russian and German) was transferred to the USA, and consequently this was a major reason for the USA to rise as a super power in the 20th century.
Was there a boost to the US economy that was bigger than the US could have achieved by itself? And what would that have meant for the parties concerned in terms of geopolitical presence.
Holy hell, a question that I can not only answer, but that DIRECTLY relates to literature I'm currently reading, namely, Thomas Picketty's Capital. So, in part, the transfer of wealth from Europe to the US during WW1 was in part a direct transfer, and also as a result of economic stagnation or destruction in Europe.
As for direct destruction of wealth and economic power, there were regions in the wealthy parts of Europe, namely Belgium and German occupied France, that were decimated, especially with regards to agricultural and industrial potential. This was either as a result of collateral damage from battle, or sabotage to prevent the enemy from making use of this valuable equipment.
Another less tangible version of financial destruction was the devaluation of financial investments due to either the loss of colonial land, inflation created by a need for governments to pay off debts accrued from the war, or massive drops in the value of financial assets created by the weakness of a global financial system whose major participant nations were slaughtering one another by the thousands.
To give you some example of how valuable foreign assets were to the major participating nations of WW1, net foreign assets had a value of 50% of national income, of GDP in Germany at the onset of the war. That is to say, the value of foreign assets held by Germans, subtracted by the value of German assets held by foreigners, was equal to 50% of the total income of all assets in Germany. Further, Germany was the most nascent of all colonial empires, had the least amount of net foreign capital. France's net foreign capital amounted to 150% of GDP, and Britain's, 200%. After the war had ended, the value of German and French foreign capital was either zero, or negligible, and the value of British foreign capital had halved. That being said, as it applies to transfer of wealth, this is not a direct transfer, but rather, a destruction of wealth that allowed the US to "catch up" to Europe.
Beyond foreign investments, and with regards to all investments, the total value of capital in relation to GDP in Britain and France went from roughly 7 to 1 in 1910, to roughly 3 to 1 in 1920. In other words, over half of the value of ALL capital was eradicated. For reference, a comparable destruction of wealth in the US with todays national income would amount to 75 TRILLION dollars. German capital underwent a lessen destruction relative to national income, but that was largely a product of a greater destruction of national income.
The US saw no such damage to capital, and instead saw their capital to GNI(gross national income) level rise from a pre war rate of about 400% of GNI, to about 430%, representative of a steady growth.
Now, the US avoided damage to physical capital and received a benefit to industry as the arms industry flourished, and demand outpaced European production, creating and encouraging a thriving arms market in ostensibly neutral nations like the US and Spain, though in the case of the US, the vast majority of arms sales were to allied nations.
So, I'd argue that the US's elevation to superpower had less to do with a direct transfer of wealth from Europe to America, but instead, it was the product of the destruction of European wealth, coupled with American growth. In the post war period, America did not have to rebuild its economy or cope with nearly the population loss or physical damage of the European powers.