I travel a lot for work and pleasure. And when I travel, I carry with me equipment to tune in and record local TV. I've been doing this since the early 1990s.
Here's what I've learned from the DTV transition:
In the analog days, when I was hauling two or three VHS VCRs on the road with me (plus a box of blank tapes!), I learned pretty early to call ahead as I was making hotel reservations to determine whether the hotel had the local cable system or some sort of roll-your-own MATV system. Sure, I carried an OTA antenna with me, and a pretty decent one, too - but even right in the window of your typical hotel, you just never had any sort of guarantee that the reception would be clean enough for a good recording. Multipath! Ignition noise on low-VHF! It was a crapshoot, at best, just to get a clean tape of the local news or (back then) the sign-off/sign-on announcements.
Since the DTV transition, I've probably had the opportunity to test out OTA reception in 140-150 of the 200+ DMAs out there. (Biggest one I'm still missing? Memphis.)
My current setup is a Terk HDTVa antenna (no longer in production, as best I can tell, but still available online) feeding a HDHomeRun 4-tuner box, connected by ethernet to my laptop and a hard drive. It's a LOT easier on the luggage weight restrictions than the VCRs were!
Is it perfect everywhere? Absolutely not. Some markets are difficult verging on impossible: when I'm in San Diego, the relatives I'm visiting are up in North County, where OTA reception of NBC, PBS and indie KUSI from Mt. Miguel is essentially nonexistent. Same with NYC, where the free room at my cousin's house is up in Rockland County and there's no outdoor antenna that I'd need for clean reception. The VHF signals in Cleveland always seem to be troublesome no matter where in town I'm staying. There's no one spot where everything in the spread-out Hartford-New Haven market all comes in at once on an indoor antenna, or if there is, I haven't found it. Same for Grand Rapids-Kalamazoo. My buddy in Denver who lives pretty far out to the southeast has trouble getting the Lookout Mountain VHF signals on an indoor antenna unless I position it juuuuuust right, mostly because of distance. The Orlando signals are far enough east of town to be tricky at some of the hotels out by Disney World, to the southwest of Orlando; depending which direction the rooms face in, you might get more of Tampa, as I did a couple of years ago.
But those (and one more, which I'll get to in a second) have been far and away the exception. I'm actually pretty regularly surprised by how often I just plop the antenna somewhere near the window, scan the tuners, and discover that everything I need to record is right there and locked in. No ghosting. No electrical sparklies. Just clean picture and sound and lots of subchannels. (It was pushing 100 streams of video the last time I was in Los Angeles a few months ago, and out by LAX I was even getting the iffy low-band Vs like KWHY/KBEH on 4.) You can get everything in Dallas on not much more than a paper clip in most parts of the metroplex. Small markets like Elmira/Corning, Utica, Watertown that might have had one V and a U and didn't get a full count of major network affiliates? They're all there now, often on just one or two transmitters. And they look pretty good, by and large.
In a lot of places, that indoor antenna even manages to get beyond the local market. Boston in October, when I was staying out by 128 in Newton in sight of the local towers? On the sixth floor of the hotel, that antenna wasn't even right in the window and was still delivering nice clear pictures on the Providence UHF signals, which were only iffy at best back in their analog days. The same, even more so, in reverse from my buddy's spare room on the second floor of his house in East Providence, where I could see nearly all of Boston without even trying. And all of Baltimore, VHFs as well as UHFs, from out near Andrews AFB in the DC suburbs just a few weeks ago.
My point here, if you've read this far, is that I probably have as much experience with the real world of OTA ATSC 1.0 reception in mediocre indoor environments around the country as anyone these days. In 90% or more of those situations, I'd gladly take ATSC over the old analog era. (And in the other 10%, I was probably depending on cable anyway.)
Oh, that last exception? Phoenix. The college friends I stay with when I'm in town live way up north up Cave Creek Rd. outside Loop 101. Their house is typical stucco and lath, and the guest room gives me fits trying to get the VHF signals every time. It's the combination of distance to South Mountain, a Faraday cage of a house, and probably not enough power coming off the mountain. But one time when I stayed with a friend over toward Scottsdale and stuck my antenna on the balcony outside his second-floor condo, 8, 10 and 12 all looked nice and clear - and I was getting a couple of Tucson signals, too. (KTTU, if memory serves.)
Which is to say, I agree that Phoenix is a challenging market - but also that it doesn't represent the majority of DTV markets nationwide that way.