There's not enough listenership or awareness of HD Radio to do that. The majority of HD subchannels exists for one of two purposes. 1) To feed a translator. 2) So a streaming channel can get the music licensing rates for a broadcast station.
KNX billed $20.8 million in 2023, which is fifth best in the market. And also the top non-iHeart owned station. Only KIIS, KBIG, KFI and KOST were ahead of it.
Music genres are very fractured.. And Alternative is split between two stations which combined in Los Angeles do quite well compared to many other major markets. That's an apples/oranges comparison. News affects anyone to at least tune in at some point.