Hodgie,
I don't disagree with you at all about running twice a day. And neither does Lydiard or Lydiard diciples Wetmore and Liquori. What all of us would tell you is that if you are going to run less than 100 miles per week, you should not break it up into 2 runs per day. Both Wetmore and Liquori will cite pratical reasons. If you go to two runs per day you are significanly adding to the amount of time you are putting into the sport with the extra showers, stretching, driving, etc. Liquori says don't go to twice a day unless you are going over 100 per week. Liquori averaged 110 to 140 during his prime.
Lydiard would say, and I agree with him, that running 100 miles per week in singles will result in much faster improvement than running 100 miles per week in doubles. So if you are going to go 100 or less you should not double in Lydiard's opinion and I agree with him.
My original point was just to say that running 85 per week in singles is much tougher and better for you than running 95 miles per week in doubles.
Now what about running more than 100 miles per week? Lydiard is all for it and so am I, provided 100 miles of your running is at a strong aerobic effort and the rest of the miles is at an easier pace. Lydiard's books say this and so does my thesis. The reason I am not saying we should have everyone go out and run 130 miles per week right off the bat is because of the terrible state of distance running in this country and the Runner's World mentality engrained in the coaches that got us here. Hodgie and Malmo and all the other old school guys know what it takes. However, and this is a generalization that does not apply to everyone, we have a whole generation of runners now who think running 70 miles per week is dangerous or too much, a whole generation who thinks you have to take 10 years to build up to 90 miles a week. A whole generation that thinks 95 miles per week is crazy. Let's get em up to 100 per week, then take on double later. See my point Hodgie?
PS Last I checked 0% of high school runners and less than 1% of college runners were running 100 miles per week.