Sorry about the Harbor grinder (those things are pretty "plasticy" not very "fluent.") Beranek in his "Bible" specifically addresses the question of exact sameness of tooth length, and says (basically, interpreting here) that, within reason, it doesn't matter. That , in essence, each tooth will cut if sharp. There are those - who do have a point - who say that to have that lovely sensation of "smoothness" of cutting in the wood, one wants very equal teeth. (But there are a lot of us who are mostly trying to get work done capably, comfortably and efficiently, and gratefully accept a chain that just cuts well.)
I don't think anybody advocates leaving "dull teeth." (Most of us, I believe, will cut back to somewhere near the little angle marks on top of the cutter as necessary, and then toss the chain when it is "done.") I'm not sure that the high speed video you describe would be especially helpful resolving the issue of exact cutter length, because all sharp cutters would (do) each cut a small "chip", and the question, I believe, would be about the uniformity of the chip size -- which varies anyway with changing saw angle and differences in the wood.