Well the fact of the matter is, for the most part, most "oldies" stations today are actually playing more of a classic hits format. The playlists are more focused on the 70s, with some 60s and early 80s thrown in. This is basically where WCBS-FM left off before they turned into Jack FM. I think the problem with WCBS-FM was that they were evolving too quickly going well into 80s music before the Buddy Holly and Frankie Valli fans knew what hit them. I think that WCBS-FM would be alive and strong if that evolution was slower, similar to what WODS/Boston is doing. And even so, if CBS Radio really wanted a Jack station in New York, they should have put it on 102.7, since they were already having an identity crisis and didn't have as many loyal fans as WCBS-FM did.
That being said, WQCD-CD 101.9 has many loyal fans, yet with what we've seen over the past decade with format flips (rock WNEW, oldies WCBS) which involved displacing many loyal fans of their respective stations, don't be surprised if/when CD 101.9 flips to something non-jazz.
On a related note, I was traveling with friends last weekend in Brooklyn, and as one of my friends was scanning the radio dial for something to listen to, she remarked that "for a city as big as New York, there's nothing on the radio." Instead of innundating the market with a number of stations playing basically the same thing, let's have our stations actually have substantially different formats from competitors. What are the only commercial stations in NYC that have a format to themselves... WAXQ (classic rock), WQCD (smooth jazz), and WQXR (classical). Most of the other stations are variations of top 40, urban, AC or Spanish. And it's WQCD and WQXR that have been rumored to flip recently. Hmmm... sad sad.
Jacko