That's what boggles my mind- as "questionable" as DirecTV quality is, I can't imagine how much worse digital cable could be, and yet the precedence is there. I imagine a lot of people are coming from really, really bad analog cable and dodgy digital cable services, so DirecTV ends up seeming like a godsend. It may well be to them, as it does manage to deliver on its primary purpose and do it better. However, it also scares me that this is what will become "accepted" as acceptable quality for the future of television. One would think as technology progresses, so will the quality of video in television, but what we are now seeing is how deftly can these service providers skirt the bounds of "passable" using the flexibilities inherent to a digital medium (which begs the question as to what purpose all of these high resolution TV's and high performance connections are really for when the state of video is moving more towards VHS than HDTV with regard to network broadcasts). There is no strive to achieve newer/higher standards in video, just be better than the worst.
You don't have to look hard, but indeed, all of those artifacts you mention in your prior setup are still present in DirecTV- just on a more subtle level. Just like you mention, scenes with rolling fog/smoke will trip up a low data rate MPEG2 video feed. Additionally, there's pans over grassy areas, noisy dark scenes, gradations from bright colors to black, fades between scenes, chronically soft looking picture on any scene that literally isn't a still frame, lack of color saturation, and many, many more. All of these things cause problems with aggresively compressed digital. It may be on the edge of perceptibility, but why not (I ask) make it a good safety factor on the side of imperceptibility? It just goes to show (to me) how borderline the precedence is right now- not very promising for the future of video. All of this screams to me that the motives have become "what can I get away with" rather than "how much can I get out of the given medium". It's a sad state of affairs, but I have found that most people are just not that concerned about it as long as they can get a solid picture w/o snow and ringing.
If it means getting only 60 channels with true, industry-leading digital quality vs. 200 channels (most of which are shameless duplications of what amounts to be the same programming) in mediocre "Quicktime" quality, so be it. I'll take the 60 in a second. My mantra is don't accept the current state of video quality simply because it was better than what you had before. Consider what the medium is capable of delivering given the technology, and then challenge the current state. Believe it or not, a decent, modern analog cable system walks all over DirecTV in video and sound. True, not everyone has access to a better analog cable service. However, that should not mean that you don't demand at least that level of quality from your chosen satellite TV service.
Don't even get me started on the quality of basic stereo sound...