In terms of nominal GDP per capita, the US is around $85k with Poland at $25k, so US GDP would need to fall around 70%, which would be an unprecedented fall, the kind historically only associated with mass bombing or extreme hyperinflation.
Good thing we're not talking about GDP then!
GDP is irrelevant when discussing the well being of the ordinary person. A more relevant measure would be median income together with purchasing power parity.
US median income is just over 19 k international dollars, Poland is just under 9 k. Still a big difference but just over a factor of 2 instead of over 3.5.
See https://worldpopulationreview.com/country-rankings/median-in...