I hope you know that engineers don't actually physically build the bridges themselves.
That's what tradies are used for, engineers are the smart people who build the bridge with their mind and then the tradies come in and physically put it all together by following instructions from their well payed boss, the engineer.
Actually the engineers instruct the foremen, who then pretend to know something about engineering as they pass the instructions onto the lowly tradies.
Have you ever been directly involved in a construction of a building?
You have underestimated the knowledge and experience of those 'lowly tradies'. The statement he has made is far from the truth.