I'm going to address these points separately, to make the context easier to see.
I would argue that most of the problems you mentioned, insanely frustrating as they may be, are less due to HDMI in and of itself, and more due either lesser quality cables, bad implementation of the tech (CEC/ARC), or lousy initial installations (who puts a coupler deep up a wall?!)
The homeowner did that over ten years ago, having read that it was OK. It wasn't a matter of being cheap, it was a matter of A) he's able to to it, B in interested him and C) he likes doing that kind of thing. The problem is that nobody knew what would be coming from HDMI ten years later.
When I was there the last time, I replaced an HDMI in one of the systems because it just wasn't passing video. I think it was Munster, but I don't remember now- might have been one of the cheapo cables used by the satellite installer.
The long one I had to replace was from Key Digital. The fact that it failed was bad enough but when I called to find out what I should do abut it, their CS told me it had been disco'd more than four years before. The problem there is that I had bought it less than three years before the install and ADI sold it as a good product. Key Digital doesn't want to cover it, even though their warranty was three years at that time. The last e-mail I received from them was from the national training manager- here's a quote-
"If you are concerned about replacing a wire in-wall you may consider removing the HDMI heads and terminating with CAT6 STP RJ45 head as there are 4 individually shielded pairs (among other wires) inside of the Key Digital HDMI cable.
After terminating, you can use the cable with HDBaseT extenders. Our current recommended part is the KD-X222".
Oh, so I'm supposed to cobble this together and use something that sells for $300 (and charge the client), with no guarantee that it will work reliably?
As an integrator, I've seen component cables slide off of people's equipment with ease, maybe causing blue to go out. I've seen coax get ruined by a somebody destroying the cable deep somewhere. Those were not the faults of the technologies. They were external factors.
I saw that, too- usually because whoever made the connections didn't make sure they were snug and nothing was pulling on the cables. I have seen a lot of cables pulled tightly over the edge of lumber, stapled through, pounded on (Romex staples), huge bundles with all of the weight hanging and unsupported, cable ties pulled incredibly tight with signs that a pliers was used to break the old ones. Romex staples to hold HDMI and Category cabling in place are my favorite.
The frustrations you experienced are not only one reason we all believe in conduit, conduit, conduit, but ALSO for longer runs why I love my baluns. Perfect for when a customer upgrades their TVs, but all their gear is centrally located in a rack a mile across the house, but now we don't have to run any new cable in-wall! Just swap out baluns and some cheap little HDMI cables with the latest specs. Some of my best customers who had existing setups with old component cables thankfully had some installers with a little bit of foresight and ran everything via Cat5e. Made for an easy upgrade!
Ever use Spectrum baluns? I did, once. Didn't work at the BD players highest res, which is 1080p, to a Panasonic V series plasma through a Denon AVR. The total length to the TV is over 60' and the install was done in about 2011, so I installed 2" conduit and plenty of cables. I dumbed it down to 720 and it worked. I'll post a photo of the paper they included, with the instructions, later. Total joke. When I returned to my place later, I found a card from a distributor with an offer for a free pair of extenders and all I had to do is call to talk about their products. Worked perfectly and it's still there- not a single problem, out of the box. If I need to add/replace cables in ALL of my installs, I have always used conduit because I do mostly return business and referrals, so I assume I'll be the one doing future work.
And that's just it. With a bit of forethought, good quality cables, only using CEC/ARC when the gear allows for it to work seamlessly (which is rare), and the ability to upgrade easily, I have just not found HDMI to be near the headache that many others have found it to be.
FWIW, I have entirely switched over to Snap AV's "Binary" brand cables. They have those little prongs on the cable heads so I've never, ever had a cable slip loose. Excellent customer care too.