Comment by acdha

I think they were just engaging in time-honored speculation about how different history could’ve been had a few historical accidents changed. For example, the Mayan civilization collapsed about 500 years before the Spanish showed up due to the worst drought in something like 7k years, so people have speculated about what Mesoamerica might have looked like when contact was made of those millions of people hadn’t died. Repeat for having draft animals, not losing the immune system lottery so badly, etc. Given their martial traditions it’s very plausible that in slightly different scenarios the arriving Conquistadors would’ve been killed or captured and lead to return expeditions.