Not only is the idea that the Inca carved these perfect stones with soft copper and bronze tools rather ludicrous, but the idea of hoisting them in the air or constructing massive ramps is equally without merit. People can speculate all they want and come up with fanciful ideas of anachronistic tool use or architectural habits, but that does not give any real indication of how the well-known the zigzag wall of Sacsayhuaman was built.
Elsewhere in the architectural sites, you can clearly see "bruise marks", which are white marks on the stone caused by hammering that occur when the Inca used their common tools to shape rock. Since these are a common feature of the smaller stones unequivocally identified as Inca shaped, why would these marks not exist on the megaliths that make up the wall?
The Inca architecture did not use massive stones. Most of their blocks used for walls, temples, towers, and other buildings were basically cubes that fit together much like any more modern stone or brick building would. In fact, many of them were destroyed by the Spanish who took apart the stones so they could build their own buildings in the style they preferred. The massive rocks used in the wall could not be moved and did not suit any other building project. If the Inca had some simple way to transport them, the Europeans undoubtedly would have found a way to make them use it for their benefit.
Another thing that made it quite easy for the Spanish to use the square blocks that the Inca created or stones directly from the fields surrounding the planes and hills was their knowledge of concrete. This soft and pliable material made sitting the smaller stones together quite simple. However, it did not provide the same strength needed to withstand the earthquakes that plagued the region. The Spanish did not know anything about these tremors from their time and building experience in Europe. It is interesting to note that these softer constructions have fallen over the years more so than that the megalithic walls and temples created by the people who came before the Inca. Those have stood in place in movable and as precise as ever for thousands of years.