I'm surprised that a 30.06 is considered expensive. It got its start after the great war (WWII) when most of the GI's were allowed to return to the states with their rifles in tote (M1 Garand). I am guessing on the statistics, but I would be willing to bet that it is the most common deer rifle on the market.
As for overkill. I don't think there is such a thing when it comes to making an effective kill. A 12 GA shotgun and slug will make a much larger hole and do more damage. I would say that the 12 GA is more common, since many areas do not allow rifles for safety concerns.
I agree that big bucks do come out and do crazy things when the rut is on. It is a magical time of year when you see them running all over the woods. During the rut/post rut they typically won't come into a bait pile when love is on their mind. My statement was that the Big Boys won't come "IN" to a bait pile during the rut, not that they won't come out during the daytime. They will come out, but they aren't looking for some apples.