I guess I don't understand this question? Do you guys actually hunt where you know exactly how far you'll be shooting each time? If so, I guess it would be easy to decide if you can take out the rifle with the open/iron sights one day, or a scope another day. As for me and most guys I hunt with, we really don't know how far off game is going to appear- 20 yards to 450 yards at any time during the day would be typical.
Since I don't know which range I will be shooting at game, all my hunting rifles wear scopes except a couple .22's I own. I don't take the scope off for the day so that I can shoot within my set range for that particular day. So, if you're using irons and you see game beyond your self set range, do you just let it walk?
To me, being prepared for whatever comes your way is hunting and a scope fills that bill better than any other system. Your mileage may vary.

Bob

Never underestimate your ability to overestimate your ability.