Something something, technological progress is not easily measured, and has problems placing one standard over all world cultures, blahblahetc. I get the feeling you're not looking for that sort of answer, and I don't want to write it.

So let's talk about some amazing technological advances South Americans developed since the Peruvian cradle got started, eh? We'll leave the historiography to someone else.

Suspension bridges! The Andes are well known to have gorgeous suspension bridges of rope that span immense cliffs and rivers. Control of these bridges during the Conquest enabled the Inca state of Vilcabamba to cordon itself off from the rest of Viceroyal Peru, if only for a time. One of the most important river crossings in the Andes was the Apurímac which is a huge river, very dangerous even today. Well, recent archaeology has shown that sites like Espiritu Pampa (which is the best candidate for the site of Vilcabamba) had Wari occupations some seven hundred years-ish prior to the Inca presence there. Espiritu Pampa is located in the yungas, only 1000m up and on the edge of the Amazon. Why would the Wari go outside the Andes?

As we understand it now, to get around the Apurímac. That river was so intense - and the Wari had no way to get around it - that to establish trade between the regions of Ayacucho and Cuzco their trade route took them east, outside the mountains, to get south to Cuzco. So yes, on the one hand Inca roads and trade routes built off of their predecessors; but on the other, they seriously iterated on this model and unified South America as had never been done before.

Improvements on hydraulics were also made over the course of Andean civilizations. The Wari in particular had some incredible engineering feats; for their largest site outside the capital, Pikillacta, water was diverted across (or more precisely, around) the Lucre Basin via canals that followed the contours of the basin. These canals put together are about 48 kilometers long, and their average incline is on the order of arcminutes - some of the flattest, most impressive canals in the world. These canals likely took almost as much labor and investment as building the site of Pikillacta itself, and were also a discrete stage in the construction of the site, as the major buildings supplied water are atop the final destinations of the water supply.

With regard to environmental alteration, extensive terracing was also developed - most noticeably by the Inca but to an extent by other mountain-dwelling cultures as well. Many Andean valleys have steep inclines leveling out into broad-shouldered peaks; the choices to cultivate are either valley bottoms (with the associated risk of flooding) or high up on these "shoulders". This naturally spread out communities and kept population density relatively low. Terracing up steep mountainsides, well past 45-degree inclines, opened up more land for cultivation, and also encouraged the "vertical archipelago" model of agriculture, wherein a farmer or community can grow varying crops according to their preferred altitude. This is part of the formula the Inca heavily utilized, and what helped fill their storehouses to bursting.

Hey, I've got to get to work but I'll keep thinking about this question today, and perhaps amend my post with some other awesome ideas during lunch or something.