US leagues are built on franchise models with massive owner investments and stadium deals tied to cities. Relegation would tank franchise values overnight and no owner is signing up for that.
No. US leagues thrive on parity, drafts, and stable franchises; relegation would punish bad seasons by gutting fanbases and wrecking local sports economies.
Relegation is exactly what US sports need to kill off tanking forever. Make billionaire owners actually sweat for their TV money instead of coasting on guaranteed profits.
US leagues thrive on closed systems that protect big-market investments and guarantee star power stays put. Promotion and relegation would tank small teams and kill the cash cow.