By that analogy you should be thankful to everyone everyday since everyone farm the fields, build the roads, build the trucks, drive the trucks, clean the roads, distribute the food, build the warehouses, run the logistics software, etc that put food on your table everyday.

Also, those engineers and designers came from other fields because there wasn't a real PC industry until Steve and Bill came along. Even those engineers that worked with him commended him for being able to see the bigger picture.