So where does KRTH get the audience for its revised format?
I assume that it will lose a portion, maybe much of the old audience, unsaleable as it was, but it needs new listeners and presumably they will have to be lured away from other stations, unless there are a whole of former radio listeners who will come out of retirement to listen to the new KRTH. Barring that, which stations?
In the church business they have a saying about how a pastor who replaces a preacher who served for decades is always going to be an interim pastor, because no matter how hard he tries he'll get compared unfavorably to the old-timer. I suspect that will happen with KRTH and it'll take a couple of PD's rotating through the building before they come up with a workable replacement, if that's even possible without completely blowing out any traces of the legacy format.
Gosh knows Los Angeles just doesn't seem like the market for a station for nostalgic gringos: someone who was 21 in 1983 is 51 today so all this talk about 80's music doesn't sound like something that will bring in loads of young blood.
But then how much change does CBS really need at KRTH? Are they losing lots of money or are they making a profit but maybe not as much as they think they could with that signal? In watching 103.7 in San Diego, it's clear that CBS is not necessarily loaded with good ideas for new formats: they've changed that signal's format every couple of years or less for at least 16 years that I know of. They finally found one that seems to be working, but it took a while, to say the least.
So then, does KRTH need a major tweaking or a rebirth to be viable?
Here's what you need to understand:
No one who buys advertising looks at overall 6+ numbers.
If the listeners in the unsalable demos leave:
a) It has no effect on the salable demo.
b) The salable demo is now a larger percent of your overall audience (looks impressive with side-by-side pie charts in your sales materials)
c) Your average listener age drops and becomes a lot closer to the center of the demo.
As to how they get more of the new listeners, the same as every other station that makes a format adjustment: Advertising, promotion, word of mouth, second-hand exposure in businesses and other public places and by listeners tuning around looking for a song they like. People still use the "Scan" button.
One of the things that has always amazed me is people's tendency to write people younger than themselves off as kids.
While it is true that many high-school and college students don't own radios, KRTH is targeting 40-year-olds.
These are grownups...Moms and Dads with Tweens and Teens and jobs and mortgages.
And radios.
KRTH has a lot further to go than, say, AMP, before they run into the "what's radio" problem. Actually, if you buy that particular prevailing wisdom AMP and KIIS should be gasping for air by now. Clearly not happening.
Finally, your "nostalgic gringos" comment.
KRTH's current sound has decent ethnic appeal. Yeah, the music probably is still a little old...but now, they're in a better position to evolve it steadily over the next few years, with a group of listeners who will perceive it as KRTH getting better.