the best picture quality on a tv set doesn`t mean much when with OTA reception to those who struggle to get a consistant signal
That's not a lot of people. Most everyone I know has cable or satellite for their HD needs. I have a small log periodic antenna on the roof with a 25dB amp and can get all of the Philly stations, 80 miles away (I'm in a valley too) except the boneheads who stayed on channel 6. But I'll bet I'm the only one in the neighborhood, or even town, that does that!!
It would be cheaper for the TV stations to shut it off and buy each OTA viewer a satellite receiver set up to receive the basic OTA channels only. Cut a deal with DirecTV to pay them what the electric bill would cost, and the stations can save on tower rent.
AM isn't dead. FM isn't dead. 93% of the population still uses analog radio. OTA TV is on life support, and has been before the switch to digital. 15% at best use OTA. But the demand for better picture, no matter what the delivery method, was there. It isn't for radio's case. And the "extra channels" would have been cool in 1990. Now, there's 1,000's of "extra channels" on Sirius/XM and the internet.