I'm late to reply, I know, but I do think that airplay in California is extremely meaningful. I realize there are other hotspots in the country for music, but California is one of the few places that has consistently set trends for the rest of the country. There are a lot of people in California, and a lot of bands competing for the spotlight. It's not like me getting my band played on the local college station. Read a handful of band bios, and see how many times people mention "KROC" in the same paragraph as the phrase "big break". Maybe I'm biased from listening to so much California music, but I think it's noteworthy that people all over the world know of that station. Radio play in other places, regardless of how far removed from the band's headquarters, is comparitively almost trivial. I could get all the stations in Maine to play the new Ozma record constantly, but combined, it's probably a fair bet that they would have less meaningful impact than KROC's endorsement.
And seriously, lack of availability in stores does slow people down from buying a record. Say I'm on the fence about buying something. I'll go to the store with my fourteen bucks, and see if it's there. If it's not, I'll just go buy something else. I'm not going to turn around and go home and buy it on the internet. If I really really want it, I will, but if my interest is more casual, I'll just invest my money into other options that are readily available with no waiting. I only own two Mirah records because that's all the record store ever caries. If they were in stock, I'd have her entire discography by now. It so happens that the part of me that buys records is the impulsive part of me. When I get home, I have time to think about it, and I realize that I have too many fucking bills to buy more CDs. So instead of ordering a copy of "Storage Land", I make do without it. I am NOT the only person in the world who does this.