Solomon uses a metaphor to paint the importance of wisdom today — 

Ecc 7:19  Wisdom strengthens a wise man more than ten rulers who are in a city.

Throughout the Old Testament, we see the mighty Kingdoms of Israel being toppled by the Assyrians because of their idolatry.  Rather than being wise, and keeping God’s commandments, they became fools and disobeyed God’s law and indulged in paganism.  

Just because someone has a mighty army, doesn’t mean that they are necessarily wise.

A more contemporary example of this could be Hitler, he had an immensely large military but he was humbled in the worst way, and the invader suddenly became the invaded.  It is better to be wise and obey God, than be an arrogant fool and face God’s wrath.