this position is the key. Do not focus on *just* the elbow. Look at the entire position.
A good exercise would be to put yourself into this position in freeze frame. Now, does you throw have anything to do with this position? No, not really. You never achieve this position. This is the true power position.
THIS POSITION IS NEARLY UNIVERSAL AMONG GOOD PLAYERS.
Your throw is pure arm whip. Your arm whips around your body rotation (very nicely I might add). You can throw like that, but the distance potential will top out early. The "big snap" come from loading the elbow into this position over the top of the lead leg. Your elbow is never getting cocked to a great extent. Your hit over your left pec instead of starting at your right pec.
The rotation of the swing must transfer from the rear of the body to the lead leg. For the finish of the throw, you are actually rotating around the front knee, not your center. That is why the rear leg is very nearly off the ground.
This rotary weight transfer is part of the power coming into the hit zone. The weight shift from the land leg in the X step to the front leg is part of the "snap load" of the body. Firing the rotation to the front "center of rotation" puts you into the "braced" position shown by these pictures.
Your collapsing lead leg shows your rotation is to far to the rear. Blake calls that "weight back" but I believe this is *slightly* misleading because it is not just about weight, it is about the center of rotation.
You never make any effort to get into this position. If you did achieve this position in your throw, you lead leg would appear flexed or bent.
PS: this is my biggest flaw myself. It has been immensely hard to work on. Mimicking this position shown in these pictures (even make that Avery face HE HE), and trying to throw back through this position is the only thing that has worked.In fact, it is apparent that this bent elbow, elbow forward position is so important, I now understand "true" bent elbow throwing simply *starts* from this position and simply coils and uncoils the body back away from and back into this position.
Everything else is not bent elbow.
"The reasonable man adapts himself to his environment. The unreasonable man adapts his environment to himself, therefore all progress is made by unreasonable men."
-George Bernard Shaw