There is no truth in the belief held by some that the 748 was built cheaply. At the time of its inception AVRO were deeply committed to building Mk2 Vulcans and a great deal of work with the Shackleton.
The brief was to build a DC3 replacement which would appeal to that type's users with all the ruggedness of the type, low and relatively simple maintenance plus the benefits of speed provided by the Darts and a pressurised cabin.
With no real post war expertise of the civil market after the disaster of the Tudor, working from a plain sheet of paper, having to start a completely different design and production environment and build a marketing and after sales back up operation, there was nothing cheap about getting the type in the air and in service. The long life of many of the airframes in the environments in which they were used is testimony to the fact that the build was not a cheap job either.