What is The Old Oligarch's main idea when he says it is the steersman and the shipwrights (shipbuilders) who have brought the city-state power?

What he meant was that all of the people on the ships were the ones who brought what was necessary with them. Without the ships, there wouldn't be any power.

Explanation:

adopted the practice of proskynesis, a persian court custom that involved bowing down and kissing the hand of others, depending on their rank.

no one really purchased it themselves, it was all america, they had debates etc.