H.264 is only about twice as efficient as MPEG-2 under optimal conditions. Real-time re-encoding are not optimal conditions.
A 4-6 Mbps bitrate using H.264 is still inferior to a 12-14 Mbps bitrate using MPEG-2.
The only thing "stunning" about DirecTV's picture quality is how bad it is.
Again, your spouting specs is great. However I see you also mention "under optimal conditions". I guess if I lived near the main Charter feed in town I'd be getting those conditions. But I live at the outside edge of town. Apparently conditions are not optimal for me because out here HD Charter is grainy and looks like crap. They came out and ran new cable twice over a 17 year peroid, it didn't help the picture but my internet feed is great.
So, as I see it, I can't get Charter to do what it takes to provide the optimal condition you base all your assumptions on.
However I can get a fantastic, compared to the Charter picture I get, feed from a satellite.
The bottom line is you can talk about how great something is all day from a perfect world perspective, but I get to give my money to which ever service is actually best for me. Charter gets my internet money, Directv gets my video money. What the heck, I even gave you my two cents worth.