IF and only IF receivers were manufactured with standards to receive selectable full digital or FULL ANALOG I don't see this as an issue. But...keep in mind, rolling out all digital on the extended band WON'T make it available to Joe America for a long time. Car manufacturers are not going to jump on it, and consumer radios aren't going to bother with it! They have a hard time just making a good ANALOG product anymore...
C-quam was the winner in AM stereo systems years ago, and while it was "one patent holder" and Motorola could have been called the "Ibiquity" of the day, there was no oppressive licensing fees to use it! Stations bought the equipment which supported the manufacturer, turned it on and used it! It can still do well today if.....IF....we'd get marketing of it, and more AM audio processors in the field that generate the needed L+R and L-R signals.
There is one major manufacturer of AM audio processing (Orban) protecting and including AM Cquam Stereo in it's newest processor which also can process for digital....so I'd conclude the system is not by any means dead. Just dormant for now. DTS's purchase of Ibiquity doesn't change the fact they bought a sinking ship and a technology (on AM anyway) that has failed. On FM? Well...except for limited range and very little difference from well done analog FM, ......Meh. Take it or leave it. it does nothing except provide extra venues for formats and loopholes for those wanting to outFCC the FCC's owneship rules.
Personally I have no interest in the extended band and would not move there even to up the power of WION. There's still PLENTY of non extended band radios out there, and I don't think I'd want to alienate them. FULL digital AM testing I have not heard. I don't know what it would do to other stations on the same frequency...the initial testing of this system on a large AM out East did not address the issue....Personally, I think putting ANYTHING digital on a band whose advantage is long-range ANALOG transmission is a mistake. AM simply needs, as I've always said a few things:
1) Owners that care about sound quality in their physical plants (studios to Transmitter)
2) Owners and Program Directors who put compelling programming on the air
3) Standards imposed in bandwidth use (minimal quality) on broadcasters and in receivers.
AM's survival is not about going digital. The "D" word is a buzzword, and to me a swear word. My TV reception didn't get any better, my cellphone drops out more, and Hybrid Digital was a total abortion on the radio dial. So, why not leave well enough alone! We have ONE band that can sound excellent with just some people that CARE running stations, and reasonably good equipment. Even USED equipment.
GOOD programmers and owners will survive without expensive conversions to other parts of the band or other types of transmission.
BAD ones will, as time goes by, fall by the way...just like good or bad sellers and manufacturers of ANYTHING.
By the way, if you're at all radio minded, and want GREAT entertainment, look up the public comments on FCC proceeding 13-249. What a mess! Some very GOOD points were made, some totally asinine ones as well. We now have to hope the FCC has some level headed, broadcasting-oriented commissioners aside from Mr. Pai, who are able to weed out the BS from the reality of today's radio station operators.
Hope you're not disappointed, Ice. (after waiting so patiently.)