I think HD radio could still take off...but it won't because that would take a concerted and unified effort by the industry (the radio industry; not iBiquity) to put on interesting programming and market it correctly. It's a shame to see good tech relegated to nothing more than a driver for translators. What a waste.
Why would the industry pump a ton of money & resources into it? So, a finite advertising revenue pie can be split 50 or 60 different ways instead of 20 different ways? Some theorize the original long-term plan for HD Radio was to encrypt some or all of the subchannels to make them a subscription service. Whether or not that theory has any merit - I honestly do not know.
Sound quality was never an issue among 95%+ of analog FM listeners, so we can remove that argument from the table, too.
For AM band programming, signal issues and lack of mainstream programming are the biggest issues (the signal issues are the main reason mass-appeal programming has left the AM band in droves during the past 20 years). IBOC digital transmission on the AM band does absolutely nothing to resolve either of these issues. In fact, I would argue degradation to analog audio quality + increased noise caused by AM IBOC hastened the deterioration in AM band cume. Of course, you'll never see the FCC, iBiquity or one of the corporate media behemoths commission a study to research whether HD on AM has been a help or hindrance to the band's viability. They're afraid of the truth.
In my home market, I've seen signal-deficient AM stations with 1.0 or 1.5 shares before IBOC adoption deteriorate to a 0.5 share, and ultimately, a 0.2 or 0.3 share following its adoption. I am not saying IBOC is the sole cause of the ratings decline, but what I am saying is that clearly it has done nothing to improve the long-term viability of these stations. AM stations that used to have an enterprise value of $10 million or even $15 million have recently been sold on a "stick value" basis for $3 million or less.
Earlier commenters hit the nail on the head; if it weren't for the FM translator loophole granted by the FCC - HD Radio would be in even bigger trouble than it already is!
The technology (from an adoption rate standpoint) was doomed from the get-go when the "brain trust" (read: idiots) behind this technology decided to force FM listeners to tune to the parent station as a pre-requisite for being able to access the HD-only subchannels. And, again, why would big radio stations have any incentive to push listeners away from their cash cows to HD-only subchannels?
Once the AM band has deteriorated to the point where it is little more than a carbon copy of shortwave, the industry and the FCC should consider the following:
--#1: Setting a timetable to convert the AM band to 100% digital
--#2: Requiring all AM/FM radio manufacturers to include digital AM reception technology in their receivers in order to sell those units in the U.S.
