Yes and no. Another doe will take her place in short order. However, it may be a young doe that isn't necessarily ready or wise enough for the task. Just like our grandmothers, an old doe has a lot to teach the younger generations. Lots of wisdom and she rules the herd, dictates who gets first crack at food, fawning grounds, etc. She keeps order and maintains a level of consistency that a younger doe simply cannot.
Another really important reason for me to keep her around is because she's been hitting estrus same time every year for many years, and every older buck in the area knows when. Learn that time and you can plan hunts around it. That continuity of predictable buck activity can't be bought. It's priceless for a hunter.
If and when I target does I am looking for a yearling or 2yr old. Does make new does, and those young does can be replaced by next season. But that old nanny and all her consistency takes years to replace. So I never shoot her. But to each their own.