The cost of transportation scales with density of the object. If it takes up a lot of space like insulation or a house, which is by design full of empty space, then it costs a lot to move. To decrease transportation costs you'd have to increase the volume of space available both in depots and in the vehicles doing the moving. You'd also need to make it easier to move large items. The best example of this are container ships which have drastically reduced the cost of transportation. You'd need to replicate that for land or air transport and the last mile delivery to site.