Because we're the only major economy that's relatively "open".
The EU is stagnant. Their economy was bigger than the U.S. 20 years ago. Failed to keep pace.
China is communist.
India will continue to do better but they're still a third world country (with problems due to their caste system).
I was formerly more pessimistic about the US economy in general and the dollar in particular. Then I realized the other world currencies are even more screwed up. Not to say we can’t still screw up more, and might still do so catastrophically. But we’re still the best place on the globe. Who knows, Milei may turn Argentina then South America into a powerhouse to topple us. Stranger things have happened.