Apologies if this is the dumbest of dumb suggestions, but is there any possibility that the straight track, which we're speculating might have been made by the nose gear, could actually have been made by the tail?
It looks as if the track starts at a point roughly level with the tail cone, and it's parallel to the eventual track of the main gear, as if the tail hit just as the aircraft was steering to port. Is it possible that this was the tail strike that's been mentioned?
Of course, the track is well off-centre, which suggest that I'm wildly wrong, or the tail section had partly broken off by that point and was dragging on the left, or perhaps was subject to that weird geometry we've been looking at.
And given the foreshortened perspective, it could be that my theory makes the plane half a mile long! It's just an idea.