Then China Just... Stopped

After the Yongle Emperor died, the new court decided ocean voyages were a waste of money. Confucian scholars argued that a great civilization does not need to go looking for anything. By 1433, the great voyages had ended, the fleet was left to decay, and the old Ming bans on ocean-going shipbuilding — part of a longstanding sea-ban policy that even outlawed large double-masted ships — were enforced once again. The detailed records were buried in the archives and largely forgotten, though key charts and eyewitness accounts of the voyages survived.

China had the best ships, the best navigation, and the best funding — then chose isolation. Within a generation, the fleet was rotting in harbor. Within a century, Portuguese carracks a fraction of Zheng He's size would sail into Asian waters and never leave.