Although there has been some confusion between satellite radio and HD radio, the two are different. HD Radio augments existing terrestrial broadcasts. Satellite radio relies on a different technology and content stream and is only available with a subscription.
Since HD Radio technology allows radio stations to continue broadcasting original analog signals, there's no need to update your radio hardware. Unlike the highly visible switch from analog television broadcasts to a digital standard, there are no plans to eradicate analog radio broadcasts. That's mainly because a cessation of analog broadcasts won't reclaim bandwidth that could subsequently be resold.
The HD Radio standard is based on technology owned by iBiquity. In 2002, the FCC approved iBiquity's HD Radio technology for use in the United States. HD Radio is the only FCC-approved digital radio technology.