When you go to Starbucks, you expect the same service in New York that you get in California... The same would hold true of a McDonald's or a Cheesecake Factory. There is a consistency within these brands that just doesn't happen in real estate brokerage brands and that can extends even within individual franchises.
What exactly is a "premier agent"? I think most buyers and sellers think that there is some nice person or department at Zillow headquarters that carefully culls the lists of agents and offers premier positions to agents that have strong track records in each particular location. I hate to burst your bubble on this, but nothing could be further from the truth.
The answer is "Not necessarily!" Most agents in Westchester County do not have a great number of listings...if any. There are a handful of agents that do and most trumpet that fact as a sign of great success.