Most training looks at the same things, aerobic gains. If it doesn't, you may as well put it in the bin, as that is what will make you better, for the most part.
I agree how you structure it can be important, but I still stand by the fact the impact of load is probably making up 90% of the picture (one of the problems I think with some running training plans is that it doesn't even allow you to fill in the 90%, before you burn out).
The last 10% everyone, especially elites are scrambling around for. I think maybe what I have evolved this into, probably fills in the 90% better than most training, but I might be wrong about that. I don't see specificity as something to even worry about, until you max out what you can gain by filling the aerobic tank. Probably that's where a good amount of the success comes from, people are maybe 60-70% full from sub optimal training and this fills the tank more over time.
I'm glad people are finding this a good way to train, there have been some fantastic results for people lately, but this isn't the only way to train.
Whether you use lactate to control or guide sessions and progression, or use a more analytical method in line with me, we are still all trying to get to the same place. The only thing really that matters is you are controlling fatigue , recovery, but understanding at some point you will need to do more (even if it's small and gradual) to get better.