Let me ask the professionals from your own personal standpoint. Ratings, numbers and reasons aside - have you ever lost a station you loved? Have you ever felt somewhat betrayed? Strong but you get the point. A radio station you felt was special. One that was more than just a dial position or a set of call letters? Mine was losing KSFO and KFRC in the 80s. And all the legitimate reasons in the world won't take the emotion away.
Sure. In fact, you and I have KFRC in common on that list. My equivalent of KSFO is its then-sister station, KMPC. And I could add KBCA-FM in Los Angeles, perhaps the best jazz station I've ever heard (now KKGO)...KFMB-AM in San Diego from 1974-1982 or so was my idea of the perfect Adult Contemporary station...KZZP, Phoenix under Guy Zapolean (1984-87) was probably the last CHR I considered my favorite radio station.
KMR and I have KNX-FM in common. But I loved KKHR (which replaced KNX-FM), too, once they worked the bugs out of the sound (they still needed a high-profile morning show and a promotion budget, neither of which they got) and I think that for most of its run, JACK-FM has been darn near perfect in terms of attitude for Los Angeles.
Having lost loved ones in my life at an early age, I know that truly important things and people aren't here forever. I'd much rather hear a radio station re-invent itself and provide a new audience with the same level of enjoyment I got from it than hear it wither away and die.
Take KMPC. The first radio station I can ever remember hearing. With the exception of Bob Crane on KNX and Dodger games on KFI, the only station my parents ever listened to. The radio station that made me want to be on the radio. By the end, in 1992 (I'm leaving out its implosion in the early 80s and a failed two-year attempt at talk), the big mansion on Sunset had a burned-out light bulb in the men's room that became fodder for Robert W. Morgan. Everything was running on a shoestring. They'd stayed too long and watched their revenue dwindle.
As for the subject at hand, KRTH exists because it spent 9 years (1976-85) as an adult contemporary station, and a very successful one, when the oldies numbers went south the first time. If it had said "K-Earth means 50s and 60s oldies" and refused to change in 1976, it would have been dead by '78 and we wouldn't be having this discussion now. It damn near died in 2005, and it was Jhani Kaye's reinvention of it (for which he was reviled by many of the same posters who now are railing against the changes to what he brought) that saved it. And now, it's been (within a few months) 10 years. KFWB's entire lifespan as a Top 40 station.
Let it (and every other station) change. Let it be relevant and prosperous. The alternative is the radio equivalent of "If I can't have you anymore, then no one can."