shuffleshuff

More likely, the Incan slave/poor populace was split and easily co-opted by the Spaniards.

Why is this either/or? The above statement is undoubtedly true, but that doesn't mean what I said is false.

The problem, is, as you say, that the Incans only had access to cloth armor, copper axes, and stone clubs, as I said in my comment. They eventually developed guerilla tactics, but such tactics are not effective when you are sieging your capital, trying to take it back from invaders. Also, I cordially invite you to try and organize the digging of ditches when 50 to 90 percent of your population has been killed, most of the rest are in rebellion because your rule was, frankly, never terribly popular, and the remaining percentage are currently facing down a thousand pound warhorse. I would also like to point out that decently training a pole-armsmen is no easy feat when you have never done it before, and your empire is in disarray.

Also, the Spanish had plenty of experience in the European style of warfare based on cavalry supported by foot, since the European cultures had access to horses for many centuries at this point, whereas the Incans and other cultures and empires that arose in the Andes had access to the llama. Llamas are not, shall we say, renowned for their martial prowess. It takes time to develop new ideas and technologies in the face of change in the best of time. Saying "oh come on, just dig ditches and train spearmen" is a tad unrealistic.

"Incan society" is a bit of a misnomer. "Inca" refers to either the ethnic group, or the ruler of the empire (so "Manco Inca" is roughly "King Inca"). About 100 years before contact with the Spanish, the Inca defeated the groups of people surrounding them (including the Chimu and Chanca), establishing the Incan empire. The last Inca to rule over a unified empire, Huayna Capac, was consolidating the rule in what is now northern Ecuador at the time of his death (probably from smallpox). His grandfather, Pachacuti, was the Inca who initially defeated the Chanca to establish the empire (or Tahuantinsuyu, as they called it).

Anyway, the point is, some of the people the Inca conquered, like the Chimu, may have had the beginnings of markets. However, the conquest of the Incas (who tended to claim that anyone they conquered were uncivilized and barbaric), and then the Spanish (who also waged an informational war), and compounded with the smallpox (which may have killed 90% of the large urban populations of South America), meant that most oral history was lost, and the method of reading the written history (if there is any, there's some debate there) was seriously crippled.

ANYWAY, getting to the point, there's some evidence but we don't really know.

It was a siege of a well-fortified town, and the Spanish had non-negligible support from non-Incan people unsatisfied with the Incan rule. That said, a Spaniard on a thousand pound horse, wrapped in steel, on an open, unobstructed field, against people wearing mostly cloth armor, with stone or copper weapons, was effectively unstoppable. Again that said, many of the non-Spanish troops supporting Pizarro and Co. died.

Most of the defeats the Spanish suffered were when some of the more clever Incan generals used the brutal terrain against them: triggering landslides, creating obstructions to disrupt a cavalry charge, etc. While that works in mountain passes, places like Lima (established by Pizarro mid-1500s), were on flat terrain known by the Spanish, so those sorts of tactics did not help during those sieges. The siege of Cuzco (or Cusco, whichever) was in a similar situation to that of Lima.

Something that I felt was missing from the Last Days of the Inca was an emphasis on the number of Spaniards, and ignoring the number of shock troops that Pizarro & Co. had recruited by that time. Remember, by the time Manco Inca had decided to "rebel", the Spaniards had been in Cuzco and some neighboring cities for several years.