As for letting nature take its course, since when do any of us do that? I don't know anyone that lets their birds totally fend for themself. We provide them with special foods, shelter, vitamin supplements, worming and parasite treatments, etc. etc.
Well.....some of us do! As much as possible, that is. Some of us don't provide special foods, merely grains and free range forage options, no vitamins, worming or parasite treatments, etc.
What folks mean by letting birds go through a natural shut down, hormonally, is so that these birds can have a normal slow down in production. If you force a bird, by using artificial lighting, to continue to lay, you also shorten their laying longevity. They burn out on egg laying much sooner. I know it's six of one and half a dozen of the other, but it still interfers with a natural thing. Even humans get a break from their jobs, why not chickens?
Winter is a hard enough time, staying warm and surviving, why make them use their energy producing more eggs?
My birds only slow down for about 4 months, they still lay but not as much. As I profit so much from peak laying times to more than make up for the slow times, this break from production doesn't matter much and it seems a fitting reward for the gals who work so hard the remaining 8 months out of the year.
Besides that, I've got folks who have come to rely on me to provide them with farm fresh eggs. I'd never keep any of them coming back if I went out of production for half a year.
I have loyal customers also and they also understand that birds slow down in the winter. They just ask me to give them a call when laying picks up and, meanwhile, they will buy storebought eggs and save me the cartons! (This also saves me money!)
If you have quality eggs, you won't lose customers over a slow time. My customers seem to appreciate that I care enough about my birds to let them cycle normally in the winter and not force them to produce by manipulating winter lighting.