The complicated sequence of stages of manufacture for each section of waveguide, took many hours. Together with the high cost and volume of the raw materials, this would have made it a very expensive technology.
The technology behind these images is described in: “Trunk Waveguide Communication” by A. E. Karbowiak, pub. Chapman and Hall Ltd. 1965. The programme at STL had been terminated by this time.
Bell Labs/AT&T continued research and development of this technology, culminating in a 14 km field trial. For extensive details of their WT-4 Millimeter Waveguide System, see The Bell System Technical Journal, Vol 56, No. 10, December 1977.