You feel that way, but all evidence says otherwise.
>and an objective measure that correlates well with this - namely, the thickness of the collagen sheath just underneath the shell
Measuring that is objective, but there is no evidence it correlates with taste at all.
>(eggs being single cells.)
I honestly don't know how to say this nicely. You expect people to take your pseudo-scientific nonsense seriously when posting things like this that clearly show you don't know the most basic facts on the subject? A bird egg is not a single cell. The ovum is a single cell, and is a tiny spec on the surface of the yolk. The yolk, the white and the membranes are all not part of the single cell ovum.
>It's an excellent correlate of the overall health and nutritional value of the egg.
Show us the evidence. That is an easily proven objective claim, so where's the evidence?
Science isn't whatever meets your expectations. While the egg isn't functioning as one big working cell, it's not made of cells, it is what became of just one cell. More here if you want the discussion. https://www.reddit.com/r/askscience/comments/ry2ug/are_chick...
As for what healthy eggs looked like, I'm guessing you haven't spent much time on a farm. The fragile, rather sickly eggs you're so used to buying now were unknown on farms fifty years ago, when I was younger.
Do these contribute additional cells to the egg that must be counted?
So any taste test that doesn't find a difference between eggs isn't testing the right eggs.
There's plenty of scientific evidence for this based on wine studies[1], but on a personal level, the tongue map myth[2] is the one that gets me. It was taught in science class as true, and we did (non-blind) experiments to measure the effect, but we failed to conclude the effect didn't exist.
[1] https://en.m.wikipedia.org/wiki/Blind_wine_tasting [2] https://en.m.wikipedia.org/wiki/Tongue_map
True, but after being served backyard vs. store eggs without being told which is which, or which feed type was in use, or that anything had changed at all, and still noticing a difference, I am confident that it is possible for the flavor of eggs to vary.