Why did the Incans limit themselves to the Andes? Why didn't they expand east into Argentina for example? They had the crop and animal package that would allow them to prosper in temperate regions after all.
Tobit said:They expanded over 2 million square kilometers, is about equal to the Western Roman empire. This is all through some of the highest altitudes and toughest mountain terrain. I would say the size of the Incan empire was already wanked in OTL,
And the beauty of it all was that the Incans did all that in a century.![]()
It's simple logistics. There's little incentive to expand beyond the mostly geographic boundaries they had for the effort required. As Bying said, there was one final frontier, ie, north, but IMO the already destabilizing empire wouldn't have been able to deal with that much overstretch.
They could have gotten further north into *Colombia, where there were some pretty wealthy cultures, but a series of unfortunate events (Smallpox, civil war and the Spanish) brought about the end of the Empire before such a conquest could have been made. So, if you delay the arrival of the Spanish by a few decades, and find some way to prevent that pesky civil war (Huayna Capac names Atahualpa as his sole successor before dying instead of splitting the empire with Atahualpa and Huascar, for example), the Incan Empire could have pushed the northern border much further north.