Completely by chance I came across the video below. It is supposed to debunk Pavel's interview with Rogan. Except that it doesn't.

This guy is a legitimate exercise physiologist/researcher. Which is surprising for two reasons. One - he doesn't seem capable of making a coherent systematic argument. Two - he doesn't seem to have a clue about actually coaching people. He believes that all your training has to be specific to the event. So if you are a miler that's all you have to do, run a mile every time you train. And you have to do it at maximal intensity. That's it. 

If it were so simple... I am guessing this character never heard of Verkhoshansky or Mel Siff. One piece of research by Verkhoshansky has demonstrated better results when cross training replaced more traditional way. Mell Siff, in his Supertraining, summarised training theory. One aspect of which is developing various physical qualities necessary for a given sport. Some of these qualities are subordinate, meaning that you have to develop them in certain order. 

Anyway, I don't have the time to dig deep into the muscle biochemistry, this subject is not my strongest. Neither I want to copy the style of the video, which is mostly filled with exclamations, sighs and self-promotion. Sure, some things Pavel says in that interview may be criticised. The question is though, how important are those things. Take an ancient martial and healing art of Tai Chi. It is based on the concept that from the point of view of Western science is completely wrong. Chi flowing through energy channels and so on. But then there is plenty of research demonstrating that Tai Chi is good for you. In that case, who cares about the underlying theory?  

It's the same with Pavel's rant on Joe Rogan. Sure, he presents it in an outdated way, but then who cares (except some seriously insecure sports scientists)? The question is, will it harm you if you decide to train using Pavel's methodology, even if the concept regarding the energy pathways involved is misunderstood and misrepresented by Pavel? 

Aerobic base is worthwhile to develop, in spite of what Mr (Dr?) Kay says. You can achieve some results with specific training, but it can only take you that far. Eventually you hit a plateau, and how to get through that is the domain of practical coaches. Not pencil pushers with "arm's length list of publications".