Now in Italy is midnight, and I had no time to read a lot of pages of posts regarding this argument. So,may be that what I go to write is not an answer about what you asked, but in any case is part of my phylosophy of training.
In my career, I tested a lot of time the lactate of Italian athletes, in many different periods of their preparation, with runners from 800m to Marathon, men and women. The group of Italian coaches (I was the technical-scientific director of Italian Federation) had the opportunity to test athletes like Panetta, Antibo, Benvenuti, D'Urso, Di Napoli, Lambruschini, Bordin, Pizzolato, Bettiol, Baldini, Leone, Berradi, Carosi, and women like Dorio, Possamai, Brunet, Fogli, Curatolo, Ferrara, Viceconte and others.
I tested, instead, few times african athletes (my lactate tests were with Christopher Kosgei, Nicholas Kemboi 26:30, Julius Nyamu 8:07, Mark Bett 12:55, John Korir 26:52 and Paul Kosgei world record holder of 25 km) because of the cost of every test (kenyans don't have someone paying these tests).
However, I saw some clear difference :
a) The normal level of the Threshold of a strong Kenyan is very higher than the level of a strong European runner. We can identify the AnT (Anaerobic Threshold) like the higher level of steady-state. In many kenyans, for example in Paul Kosgei and Nicholas Kemboi, we can find a steady-state about 6 mmol, at a speed of about 2:48 per km, lasting almost 1 hour. We are speaking about the World Champion of this event in 2002, or about the most talented athlete of the specialism (apart from motivation). These are runners able to run under 1 hr HM, at an even level of 5.5 mmol. Instead, the best Europeans (Antibo for example) were able to last about 40 min at 4.5 mmol, at the same speed of 2:48.
b) A very high level of AnT is SPECIFIC for events like 10000m and HM, that are directly influenced by this capacity. Instead, events like 800/1500 or, in another direction, Marathon, need a good level of Threshold, but, after this level, another improvement is not important, sometime having the opposite effect. In other words, I cannot run fast 800m with an AnT of 16 km/h : I need 18 km/h at least. But, if I'm able to run 1:43 having 18 km of AnT, may be that to work for raising the AnT to 19 km/h can inhibit my anaerobic system, reducing my performance.
For example, if I'm able to run at 3:20 (18 km/h) at a steady-state of 4 mmol, and I can run 1:44 (27,7 km/h) making 20 mmol, I use an anaerobic area of 16 mmol for increasing my speed of about 10 km/h. But, if I push my AnT at 3:00 (20 km/h) and I become only able to push my Anaerobic System to a level of 16 mmol, I can distribute my anaerobic work in 12 mmol, and this is good enough only for running at a speed of 27,2 km/h. In this case (this is an example) we can run 800m only more in 1:45.5.
On the other side, if I have a very good AnT (for example, 21 km/h = 2:51 / km) but this is 10% higher than the AT (about 2 mmol = 3:09, 19 km/h), I'm not able to run a good marathon because my consumption of glycogen is too high and I'm not able to phinish at the same speed.
c) Due to these considerations, I think that the problem of the Threshold is a false problem. Not always to work for raising the threshold is important, of course if you have already a good level of threshold. The threshold is the base for the SPECIFICITY of every event, only for 10000 and HM is a specifism itself.
d) So, the real problem of training is : HOW CAN WE REACH THE HIGHER LEVEL OF THRESHOLD USEFUL FOR SUPPORTING THE SPECIFIC TRAINING (That doesn't mean the higher level possible) ?
e) Under a practic point of view, I think that you take too much care about theorical principles, that don't have very much to do with the real technical management of an athlete. Many scientists tried to become coaches, and nobody was able, because are not the athletes that have to follow the official physiology, but the physiology that has to follow the athletes (and normally this is not possible). If you can train many athletes in your career, with different backgrounds, you can see that the physiological variability are too many, and you must use the best way for reaching the top performance possible.
f) This is the reason because normally I don't do any tests with African runners : because I already know what is better for their improvement, without testing every time their Threshold.
g) In any case, for stimulating a quality (in this case the AnT) you need to give stimula to the body, putting the same in crisis, having the goal to stimulate the answer of the body. If you don't do stimula enough, there is no training, and the athletes cannot repeat the same results.