TG2,
I avoided quarreling with your point about the exact timing of ball release vs post foot coming off the ground for two reasons: (1) I don't disagree with your observations about that and, (2) I'm not sure why you are convinced that "post-foot-still-on-the-ground at time of ball release" is one of the Kingdom's Cherished Rules.
I discussed the purposes I think drag-lines can be used for to the best of my ability, but I hope that I haven't tried to exaggerate their meaning or value beyond what is there.
Here are House's words about that timing in "The Art & Science of Pitching":
"...a pitcher's back foot should come off the ground at about the same time the baseball leaves his hand..."
You can read what you like into that statement, but in my interpretation, "about the same time" is not at all the same as saying "at exactly the same moment". To me, this statement allows for a range of possibilities, including guys who do release the ball just before their post foot pops up to guys that you have shown, who release the ball from .03 to .06 sec (1 to 2 vid frames) after the post foot pops up into the air.
The small minority of elite pitchers who do not fall within this range (i.e., those who have no drag-line at all) are the "exceptions" I was referring to earlier. I don't quibble with their success and I wouldn't try to change them if I could.
Still: If a young guy with no drag-line is struggling and it looks like lack of stability and balance are clear problems in his delivery, well...I wouldn't hesitate to suggest adjustments to his posture that will happen to produce a drag-line (note: None of this includes any instruction to "drag your foot"...the drag-line is a result of stable posture, not the other way around...that really would be the tail wagging the dog, and maybe that's part of the misunderstanding between us?).
Hey, thanks for the kudos on my YouTube vid clips--I appreciate it. It's a nice hobby that mostly keeps me out of trouble.