I looked at the video frame by frame (there is an extension for that in Chrome).
The bar piece of debris actually goes into the spokes. I was unsure about this, from the video it isn't entirely clear if the bar could be stuck behind the fork crown, but someone pointed out that at the end of the video you see the front wheel with spokes sheared at the rim.
The forks do not separate until the bike comes back down and hits the ground.
The damage to the downtube is, I think, from the bar flailing around. But not sure, could have been from the impact with the ground.
The rider didn't see the debris because he is drafting the rider with the camera.
Does anyone think a higher spoke count wheel makes this sort of thing less likely?