How did cortez defeat the Aztecs?

Cortez beat the Aztecs by a combination of good luck and a fortuitous timing.There is often a "superior white people" argument that the Spainish technology/warrior skills or the fear of the return of Quetzalcoatl or even the "magic" of men on horses defeated the Aztec..These suppositions are being supplanted by data showing the Aztec land were having a mega drought reducing food supplies, weakening the people and making them easy victims for foreign diseases. The reduced population of sick and starving people were easily defeated.