You've said that in a lot of threads and the problem is there is no "right music." I think you've laid out the situation in Dallas well, and why KEGL is in the situation they're in.
Radio is not in the music transmission business. Radio needs to provide something other than music. Most of the successful rock stations you list have successful morning shows that are primarily talk shows. Those morning shows are the reason those stations are getting ratings. What is KPNT without Rizzuto? What is WMMR without Preston & Steve? And what is the main element of those shows? It's not music.
I think you're right! An excellent morning show, talk-driven or not, is a major boon to any radio station, music or no music. I remember back when WKQX (aka Q101) foolishly booted Mancow in 2005, and it backfired to the point where it eventually killed the station because it turned out nobody in Chicago liked what Q101 was playing. A last-ditch effort to KPNT-ize the station
did revive the ratings to a degree but it was too little too late, and it got sold and flipped to talk (and
that didn't work out well, but that's another story for another day).
If the music selection proves to be a good fit for the market and for the audience, then the music and the morning show work hand in hand to give the station sky-high ratings. If the morning show is crap but the music is good, or the morning show is excellent but the music is crap, all that happens is some schizophrenic ratings that will keep the station alive but keep growth and listeners stagnant.
I think you discount what KPNT and WMMR play for the other 13-14 hours of Nielsen tracking, however. If the music was crap I don't think KPNT and WMMR would have the ratings they have now. Hell, back in 2019, KPNT was struggling to amass a 3 share (as opposed to the 10 share they have now), and that was with Rizzuto still having the #1. But back then listeners didn't like the music mix. They seem to love it now.
And that brings us to KVIL. John Allers correctly accessed that KEGL listeners were frustrated with the music mix and the creeping talk radio elements, and Allers started playing a moderate amount of KEGL standbys (mostly culling from 00's rock with a couple of current Active-to-Alt crossovers) and lowered KVIL's talk show elements. The listeners migrated. A
half-measure killed KEGL. When something so elementary is all it takes to put a station so far above its rival, it gives the impression that KEGL was a sick station, and whatever iHeart is trying to do to cure its ills seems to just be making it worse.
Adding more talk is only helpful if talk radio is what the listeners want, that and if the talk is of high quality. I don't get the impression that KEGL's talk offerings are what the listeners want or is of high quality.