The Gambinos rivaled the Genovese in many ways from the 1960's to the 1990's but never supplanted them as the top family in the country. And even during that time, the Genovese were considered richer, better diversified, and more sophisticated in terms of their influence in labor unions and legitimate industries. It was the Genovese who represented many of the east coast families on the Commission and had the strongest ties with other families around the country.

While Gambino had a lot of influence on the Commission, and could be considered the first among equals at his peak, there hasn't been a "boss of bosses" in the U.S. At least since Maranzano and before anyway.