I think you are presenting a romanticized fictional narrative, especially when it comes to aerospace.

When engineers were working on Apollo and lunar landers, they were working on a set of customer requirements a mile long. Roving tinkerers didn't build the moon rockets. Engineers spent countless hours in design reviews with the customer, in this case, NASA.

Roman engineers didn't build aqueducts and colosseums on a lark, or some sense of poetic destiny.