Originally Posted by BendtheBar
You're making one big, but false assumption...that people are training hard enough and progressing. Most aren't.
That point becomes obvious when people state that they have done a routine as set and then state that "it wasn't taxing enough, I felt I could do more sets" etc...which means they had not selected the correct weightload for the exercise(s); of course, this may or may not be applicable to a pure beginner routine, though even then they would feel it if they selected the correct weightload and did not underestimate what they should be using load wise.
It's a common response as well, highlighting that people are not training as hard as they think they are...sometimes, however, I also feel that the above response is ego based, in some cases.