In an interview he gave not long ago, Coe stated that he routinely got up to 100 miles a week usually running twice a day. This included 15 mile long runs. He did not do this every week but he logged many weeks at 100 miles. This was directly from Coe. I think I will take him at his word.
Another thing with Coe is that he never logged his warm up or cool down mileage this would easily add another 20 miles a week to the total.
I have not read much on the other runners you mentioned so I wont comment,
I will say that if you look at the great milers of today and throughout the last 30 years almost all have logged high mileage. Heck even most elite 800 runners are logging 60+ weekly during base phase.
If you read Peter Coe’s books and interviews you’ll find Seb is confusing miles and kilometers in interviews. Seb did a lot of doubles, even Frank Horwill outlined some of Peter’s training for Seb on his website where the maximum number of miles Seb ran was around 55-60 just short of 100K and his longest efforts under 15K or about 10 miles. Europeans, Asians, Latin Americans, Canadians, Australians, and Africans don’t run mileage, everything is in kilometers. Please realize the rest of world works in the metric system aka System Internationale.
The best runners in the world worry less about volume and more about adaptations to training, which means the they try to run a certain amount of distance at certain paces. They monitor their recovery from workouts allowing to increase or decrease volume or intensity throughout the training cycle to keep them from over-training or possibly increasing rest durations between workouts or adding new ones if they feel fresh or cutting them out if they are not adapting.
The runner who pays attentions to tempo they are running and why they are running that tempo do far better than those who worry about volume. Any coach worth his salt, will pay attention to Callahan’s previous training and send him off massive long runs and will build his volume gradually.