I got your point, but please look out of the programmer perspective. For a moment, look from the perspective of, for example, mechanical engineer: all she or he needs is a copy of AutoCad, Inventor or Catia. They know nothing about code, they do not need to modify the code, they are just use the software as any other machine. That’s all they need. BTW, there is no open source competition to these programs. Free CAD, with all respect, is not so good. Not because it is made by bad programmers; simply because making such complicated software costs tons of people, time and effort, so only big enterprises can do that, and now they are sadly capitalistic.