In Sweet Spot Base Mid Volume II, out of 25 workouts, only 6 are actually sweet spot. 10 are Endurance, 8 are Threshold and 4 are vo2 max (arguably). I think people think trainerroad is just 3 - 4 sweet spot workouts every week.
And the reason Seiler looks SS more than polarized is because he is time-crunched. Pros can do 20+ hours per week, but probably still do about the same amount of intensity. As you lower the volume, the percentage of low-intensity should be the vast majority of where the cuts are made because you still need to do a minimum amount of intensity to get the adaptation. That’s why I think this is all confusing, number of rides per week, vs. time in zone and all varies depending on how much volume you do. The thing that I think is relatively similar across these theories is the time spent in tempo, threshold and above.