Everything Was Built by People No Smarter Than You", True?
If average people built the systems we use every day, what really stops us from building new ones? Skill, fear of failing, or just comfort with how things are?
The advantage of these people over the rest maybe diverse, some edge on maths, other on memory, others on empathy, others maybe in music, sports.
But the advantage is decisive, tangible in actions and facts (in retrospective, obvious), even if not all of them reach "authority" levels, the sheer ideas most introduce in an otherwise anachronic current status quo, are enough to make the "authority" to make a change of course.
Once a new idea was analyzed by lesser minds it's for them reasonable to implement it not minding a lot about where the ideas came from, nor why or who make them come to the attention of the "authority", so they just "complete" the action pattern set up from an external idea.
In the great scheme of things, many core decisitions probably relayed on the thinking of very smart people which created the path followed by others.
Think Da Vinci, Einstein, Von Neumann.
There were many (there are), many of them, most completely unknown to the history.
The conclusion is true. Average intelligence is sufficient to build good things. The premise is false. People of greater than average intelligence contribute greatly to projects started and operated by people of average intelligence.
Unless you are the smartest.