Too much mechanical work in design

There are plenty of fully standardized things in designing buildings, such as: laying out the electrics with outlets placed in set positions in each room, routing pipes with exact diameters depending on the plumbing fixtures, etc., all of which could be handed over to a program. The problem is that nobody's developing such programs, since the market isn't obvious to developers, and it's pretty hard for one or even several enthusiasts to build a product that's easy to use and functional enough.