Originally Posted by
fstrnu
If I understand you correctly, then we are saying the same thing. Generic plans don't work.
Nearly everything works to a certain extent up to a certain point. A point which most recreational cyclists and amateur racers never reach.
Your body adapts to new stimuli. If the stimuli stays the same, the body stops adapting. However, if you increase training load via intensity or duration, then the body will continue to adapt for years (8-10 years according to some coaches).
Workouts can increase the length of the repeat, the total number of repeats, or the intensity of the repeats. There's a whole lot you can do within those three parameters and those programs (developed by elite sports physiologists and athletes) do a lot of manipulation.
Any of those "canned, generic" plans (Friel's stuff, Zwift plans, trainerroad plans) can work because they require periodic testing in order to increase the intensity. As long as someone is putting in the work, then the plan works. Case closed.