The fact is we just don't know. The science has simply not been done. The commercial industry funds the studies in Poultry science. Research is expensive, grants must be funded, results checked and replicated. Since the industry already knows that commercial hens lay well their first laying year, and, following a moult, a bit less their second year, and most importantly, know that the third year even less, the flock is turned over. Commercial hens are lighted, of course.
Perhaps for the sake of "pure knowledge" someone might one day study this matter. No one has studied the "un-lighted" hen, that I am aware. So, speculate all we wish and gather all the testimonials we want, testimonial accounts are not scientific data. We just don't know if lighting shortens a hen's laying "career".
I also agree that a hen has thousands more eggs, in potential, than she will likely ever lay. She doesn't "run out" or "use them up" in a season or two. One has to account for the overall health and well being of the bird and how this effects reproductive systems.