And it's at least trying—not shutting down the discussion with "well, it can't be done! Muh ASB!".
Welcome to any discussion revolving around New World states, especially the ones the Spanish conquered. I don't think it's unfair per se for people to have questions about obvious structural weaknesses in ex. the Aztec state that leads to their longterm survival, or even about the how of survival in a broad sense. But people can't suspend their disbelief enough to accept that it's 'handled' and that you can jump ahead say 200 years to a more relevant time where the AHC actually can be tackled, and start from there to discuss the original premise. You have to cross your ts, dot your is, present sources, and argue down every idiot in the thread referencing Guns, Germs, and Steel either directly or indirectly who are determined to act as if reading a few quotes from that book makes them qualified. And at that point you've gone offscript, the AHC lost in the void.
Let's go with the premise that the Inca are the easier state to have survive, and that they whether early conquistador colonialism as well as could be hoped . The trope I'm using to frame this is 'Britain's sidekick'. Except unlike Portugal, the Inca are far more geographically secure from Spain in the longterm.
The first 50 years are understandably hectic and fringe pieces/groups of the empire are shaved off or control lost but important diplomatic relationships and trade routes are established in exchange for Inca bullion to various Europeans for many of the material goods that they are missing, a gradual diffusion of opportunistic advisors and soldiers, etc. giving the Inca the tools needed to adapt their state geopolitically as a regional power.
The Inca 100 years later have started to rebound demographically, but were unable to escape the economic conditioning of mass labor shortages. The Mita has changed with the times, and the usage of farm animals for labor has become extensive due to necessity. Ambitious infrastructure works have gone the way of the dodo compared to the prior early Empire's construction boom, but despite it all the Inca stand steady if not tall, and are able to defend against European predation, largely from Spain as their nearest neighbor. Spanish-Inca geopolitical rivalry is firmly establish, pushing the Inca into the arms of England and Portugal that depend heavily on the threat of the Inca to restrain Spanish ambitions in Europe, forming a web of dependency that the Spanish seek to crush at sea.
150 years from first contact, the Inca have gotten demolished at sea, but have had good showings on land, finally adapted to the norms and traditions of their partners and rivals in war, and having developed their own strategies to mitigate Spanish might. Worse for the Spanish, their empire is rotting, they've stretched themselves too thin. The knives are out and the wolves are hungry for revenge for Spanish excess. Spain's New World empire while not partitioned, is leaned down heavily with much of South America lost to them between English, Portuguese, and Inca ambitions. The Inca begin to look outwards now that their realm isn't under imminent threat of local conflict and the large states in South America are nominal longstanding allies and begin investing in overseas trade.
200 years later, and Spanish military hegemony over the Inca is a distant memory. The Inca have shifted their focus to the seas and undermined Spanish routes to China trading bullion for valuable goods, and have become incredibly wealthy as a result. Inca geopolitical priorities have shifted from defense of the homeland to expansion and trade, as well as undermining Spain's last colonial holding, Mexico, by fostering indigenous revolts. That this is the only place the Inca provide resources for anti-colonialism goes without saying. Everywhere else, the Inca are no different a colonial power than any other. Inca presence is strong in the Pacific ocean, and the Straits of Magellan are firmly under Inca control to ensure a regular sea route to Europe to move Chinese goods for additional revenue.
250 years later, and the Spanish have rebounded somewhat but are in the middle of losing control over Mexico with Inca and British help. The loss of control has been decisive, and transporting + supplying armies in Mexico from Spain near impossible. The war has devolved into loyalists vs. revolutionaries + Inca and British supplies and axillaries, and has largely been a tremendous L for Spain. Still they refuse to concede that Mexico's been out of their for control for years and maintain a state of war and near unrestricted piracy against British and Inca shipping, an ironic twist of fate after England's flagrant piracy campaigns against Spain in the past. It's disruptive enough to the economies of both the British and the Inca that a coalition has been formed to end the Pirate Kingdom as the two have taken to referring to their adversary. Spanish resistance is fierce but the combined coalition has had naval hegemony for years. 10,000 Inca troops land outside Cadiz after prepping from Gibraltar and Ireland for the naval invasion alongside a large British army.
