HD radio is available to almost no one--radios are hard to find, car manufacturers place them in very few vehicles, and the cost of replacing all of one's radios with HD capable sets can be prohibitive. While HD streams are also available on the web, this also makes it more difficult to access as opposed to simply turning on an FM radio. Only a small portion of radio listening takes place via the web--the vast majority is over the air.
This is the second large market to lose classical music recently--Miami/south Florida is also losing the music due to APM's sale of Classical South Florida.