Well, not really. A lot of the Ancient Celts and Germanic tribes had a King or Chieftan who was advised (often even elected) by a council of aristocrats or tribal elders. Even into Medieval times the Anglo-Saxon Kings would call advisory sessions of their "wise men" and from this germinated modern Parliamentary government.
I think it only makes sense the Big Cheese at top in any well-functioning society would want the good will and considered opinions of the leading citizens. You can, up to a certain point, ignore the comman man on the street - but it's not prudent or safe to ignore the people who own the land, lead the military, and know how to debate in the political assemblies.
We might assume the original Senate under the archaic kings was composed of the leading members of the clans (gens) when the clans actually meant something. After the creation of the Republic, and after the political function of the clans dwindled, the Senate became increasingly a body of ex-magistrates. And under Augustus, the Senate was the Empire's economic elite, from whom Augustus could draw certain trusted individuals to help staff the military and civil commands.