First, record labels do not "force out" anything. They release songs they think will make them money. If they release more songs of one kind than another, it is because they know where the money is.
But that is a record label concern that radio has no control over.
Radio stations that play music focus on formats that will attract an audience big enough and of the right age range to be of interest to advertisers. Within a broad genre like rock, if not playing much new music gets more audience than playing more current music that is what stations will do.
There is no part of the steps to build an audience for advertisers that requires playing new music at all.
The problem within some sub-genres of rock is that the audience for new music exists, but it is further fragmented into polarized groups. So while an alt rock station may find consensus songs within its gold library, finding more current consensus songs is (and has been for over a decade) very hard. For every song that one part of the alt audience likes, several other parts will dislike it.
So, rather than playing more new music, those stations are very selective in the new music. And since the labels don't give any backing anymore... not even T-Shirts for giveaways or artist visits for interviews or promotions... there is no incentive to take risks of any kind.
Stations in the larger markets spend lots of money trying to find out which songs to play; there is no desire to not play as many songs as possible... but there is a desire not to play songs that will run off significant audience groups.
I still respectfully disagree with your finding that radio has no fault in this. I again and again present new music that is currently being played on XM in every format (the ones that aren't retro channels). To say that the music isn't out there or that the record label doesn't aggressively push out the songs has a point, but isn't 100% true. Many FM rock radio stations, like WAAF, took a hard line stance on only playing new songs by bands who were big in the 80s or 90s, or by a band that (yes) the record company pushed the hell out of. That's flawed.
I used to be a participant in your big market research. I used to get calls quarterly and rate songs that were being played on WBCN, WFNX, and WAAF. I moved states 11 years ago, and I lost contact with them, as they called me. Obviously, I didnt know who commissioned the survey. It was flawed. There were times where I would hear a five second part of a song that hardly got airplay on any of the stations, and I had to rate it and say if I think it's been played enough. Honestly, when that happened, I ensured to tell them that I rarely to never heard on any or all of the stations.
That's how your stations determine what new they should play. I stand by my original reply to CTListener. The issue with rock stations is that we are aiming for a specific demo, yet playing overplayed and now officially classic rock songs. Men 25 have no connection to My Hero or Smells Like Teen Spirit. I have that connection, but 25 year olds don't. So they go to where they can connect, to the music that resonates with them. That is newer songs. Let's face it, FM radio's decision to abandon mostly all new rock songs caused the exodus of rock as a popular format. Notice how I say "a popular", not "the popular". Your research methods are flawed. Your decisions to remain "stuck in the 90s" was a bandaid that ran its course 9 to 10 years ago, and since needed to be changed.
And, if you want to build a crowd in the future, the only way to do it is to start with new acts now, and let the younger ages find it and grow onto to it. That's the edge that currently Pop and Country has, those stations are playing anything and almost everything new. Rock stations simply aren't, and the answers I get are that its the listeners fault (the all like rhythmic), it's the record company's fault (they don't aggressively push out rock music), but it's never FM radio's fault (as even though XM proves that there is enough new rock to fill the playlist of it's new rock channel).
I was asked before what is rock, as it was stated by the person who I was debating to be a fragmented format. This was in one of the PLJ threads in the New York section. My answer is define your station. Are you a hard rock station, a current rock hits station, a metal station (I never see metal being commercially viable), a punk station? I say start with current rock hits, leave the 80s and 90s to WBOS and the 70s and 80s to WZLX. Let them be classic rock. Make WAAF be current. Get some new acts out there. Give it time to grow. I know I sound like A Field of Dreams, but your industry pillaged and destroyed new rock a long time ago. Like Wall-E, they decided to go back to the 90s, still claim that they were still current rock stations, and just not come back and actually play current rock. Well, it's time to come back and acknowledge new music. Not just a new song by the Foo Fighters. I like the Foo Fighters, but FM needs to acknowledge new music in rock.
Also, someone said that I assume people want to hear rock. I stand by my statement that the main reason for it waning is that since 2006, the FM radio industry enacted a format model that at the time tried to bring in the most listeners, but over the last 13 years became it's own death sentance. Where post 9/11 we culturally were a society focused on nastolgia. We aren't so much anymore, musically going to what is new. We did that, and its run its course. I assume that people want to hear new rock, because I have yet to see it pushed and fail. Your industry has failed to provide the listeners with it, with your flawed research and broken algorithms, regarding rock specifically. As I said before on this site, country figured it out. The answer was new music. Not just new music by the 30 year established band. Actual new music, by new acts from this decade.