Telecoms planners and installers know that new fiber network build costs are dominated by civils works (the installation of basic infrastructure into or above the ground).
The proportion of the build cost varies enormously, depending on circumstances such as the population density, projected uptake, urban or rural environment, and other local factors. Additionally, new in-ground techniques (slot cutting, directional drilling, and mole ploughing) can dramatically cut these costs.
However, where possible, planners aiming to reduce costs will try and remove the need for new civils builds altogether. One way to achieve this is to move into the world of shared infrastructure, sometimes known as "parasitic" technology.