I just watched an interesting documentary about the construction of the Leadenhall Building in London. One of the claims made in the documentary is that the skyscraper construction was innovative in being built mostly off-site (due to space constraints), with workers doing mostly “assembly” at the site of the building. For example, instead of having cement workers pouring concrete floors on-site, whole sections of floors were trucked to the location and craned into the frame. They also built entire bathrooms offsite and, again, simply craned them into location.
Is there any reason this method isn’t more widely used? It would seem like building parts at a specialized factory would result in economy of scale and thus less cost. Obviously this method is not used, so there must be more to this.