Even though I don’t agree with TrainerRoad’s training plans, I believe this message is part of the missing ingredient for self-trained athletes.
Just currious on other people’s thoughts. I have discussed this with 2 coach/scientist friends and although they agreed at a basic level they seem to both feel “it depeneds.” Seems to be the same answer all coaches give on generic concepts 
Joe Friel, in The Cyclist’s Training Bible, says it this way: “An athlete should do the least amount of the most specific training that will bring about continued improvement.”
Here is an interesting point in this article. Coach Chad is suggesting trial and error
“find your MED by trial an error…”
Now in the case of the self-coached athlete that does not have the deep background, I think that holds true. I also think many coaches take this approach at some level. What I know from the top coaches is this is not the approach they take. They know very clearly what workouts drive what adaptions and prescribe what is needed, they just need to clearly understand where the athlete is at. It’s not trial and error. There might be some experimentation with volume or possibly intensity but they don’t classify it as trial and error.
I myself believed it was a bit of trial and error with in a frame work but recently got clarification from 3-very expierience and educated top coaches this seems to not be the case or it’s potentially not the right way of thinking about it.
Minimum dose and polarization are also not the way they look at it but I believe and they basically agreed from the self-coached athlete perspective these still drive the a reasonable way of thinking.