So what is there behind the result and what is the actual service provided by an architect or an engineer?

 It may be a wrong impression that goes around in society that architects and engineers are paid for the "drawings" as if there is nothing needed to put those sets together.  Sometimes I wonder if we could go to the doctor and anticipate that the diagnosis is for free and all we have to pay is the surgery.  Well so is the research an architect and an engineer needs to do, the schematic design through construction documents phases, and it takes all the years of education, practice, licensure exams etc. in order to put that all together.  We have to examine all the loads that go on buildings and all the potential loads, including wind, earthquakes, and all other such.  We need to make sure that the staircases are designed to right proportions, there are proper means of egress, there are adequate parking spots that are accessible,  we have to make sure that the water stays out, ...you name it.