I am somewhat of an "expert" on scopes in that people continue to ask me for advice.
However, my opinion is worth every bit you paid for it, so if your expert opinion is different, then so be it.
Your great grandpa was right, iron sights never fog.
Your grandpa was right, a fixed 4x scope does everything a hunter needs. Although a 6x for those really long shots would have been acceptable.
Your dad was right, a quality 3-9 variable will handle everything from those LONG shots at antelope to close in woods hunting for mule deer.
Do you know why they were all right? Because they were probably a better shot than you are. They spent TIME with their firearm, getting to know it in and out, using THE SAME load over and over again. Your forefathers knew that it didn't matter if they had a 1 minute gun or a 4 minute gun, they knew when the range was appropriate to take the shot, and worked in closer if need be.
The deer haven't gotten any tougher, the elk haven't turned bulletproof. Old men (and women) with a 30-30 bring home the venison.
So, if you have your hunting scope set to more than 4x you are a fool, and probably a bad shot too boot. Remember, in the words of COL Cooper, "Good shooting makes up for poor gear, good gear will not make up for poor shooting."
So there is my expert opinion, iron sights or quality low powered glass and LOTS of practice.