Depends. I lived on Oahu and there were at least two stations playing local music. One was pure Hawaii music; and the other was local musicians playing contemporary but Hawaiian style, brah.
Both were near chart toppers. KCCN-FM, and KCCN-AM (now KKEA).
Likewise, radio has played Steve Poltz, The Rugburns, Jewell (Sandy Eggo ties), and Primitive Radio Gods. I would like to ask Tony Hawk, who seems to have his fingers on the local music scene.