There are carpenters, electricians, HVAC contractors, general contractors, landscape architects, plumbers, cabinet fitters, tiling contractors, painters, carpet installers, roofers, architects, etc.
Each one takes a pride in their own craft and together they build house with (hopefully) the minimum of squabbling and turf wars.
One day the process of solving problems using computers will be like that, right now we are in the dark ages.