Speculation is always around. Everything from aluminum and oil to orange juice and coffee are speculations.
Don't forget before Vietnam War USD was pegged to gold. Nixon shock changed that and leads to sky high inflation (to fund the war). The low interest rate since 2001 to now, despite the perpetual boom and bust, are really needed to fund our 20 year war. Maybe with the withdraw we will finally be able to increase the interest rate (after the pandemic is over) and slow down the inflation, so we will have a quite early 90s soft landing again.
Every empire collapse came from overspending of war to currency and debt collapse, Persian, Roman, French, China, Russian, etc.