Okay, here's my take on it.
I bow hunt from sept. to jan. with one week of rifle hunting in nov.
I am religious about scent control, some might say "paranoid"
But just this weekend I had a doe and 2 young working a salt lick 8 yards from my stand for 20 minutes.
They were up wind and down wind of me, but they never smelled me. Point is scent control works, but it is a part of woodsmanship not a replacement for it.
As a kid, I used to go down to the neighbors orchard in late summer, climb up in the trees and watch the deer as they came into eat apples. I practiced no scent control back then, and my observations were that on an average day a deer would smell me at about 15-20 yds. Some would spook others would just notice. But you could always tell when they found the smell.
I own a carbon suit, and it is one of the few things that I've bought over the years that worked as advertised. Having said that, I have had occasions where I do everything I always do and have a deer lock up on me. It may not spook but you can tell it smells you.
But certainly you can harvest a truck load of deer, just as our forefathers did, with no fancy suits, sprays, and soaps. You just might not get to sit and watch them at close range for 20 minutes and then have them walk away and never know you were there. And that's why I go to all the trouble, for all the ones I don't shoot.