What leads to poor quality in the elevator? The customer. Period. If the custom will accept a lower level of quality then the manufacturer will make it. It is up to the owner during the walk through to point out the elevator panel and say that it is unacceptable and that it must be fixed. No one else is to blame.
CAD and technology are irrelevant to this core issue. If you can complete the drawing/design in X number of hours, then you have just proved that it can be done. People worked just as hard and put in just as many long hours when they pushed pencils. Driving workers for every last drop of productivity is not a new concept that was introduced along with the computer.
If the drawing goes straight from the designers desk to the shop with no quality control, then it is a quality control issue. A drawing created using pencil and paper could have taken the same route to the shop.
Frank Gehry designed Walt Disney Concert Hall on the back of a napkin. But the engineering and plans were completed using very high powered computers. Which is the better method? Neither. The better method is the one that works.
CAD works. CAD saves time. But the quality is unrelated to the medium.