They are pushed on to the next task before they are ready. They fall further and further behind and begin living with a powerful dynamic of school failure that is reinforced as long as they remain enrolled or until they drop out. They also become prisoners of time. They get caught in the time trap as well. Conscientious teachers discover that the effort to motivate the most capable and help those in difficulty robs them of time for the rest of the class.
Typical students are prisoners of time too.
The paradox is that the more the school tries to be fair in allocating time, the more unfair the consequences. Providing equal time for students who need more time guarantees unequal results. If we genuinely intend to give every student an equal opportunity to reach high academic standards, we must understand that some students will require unequal amounts of time, i.e., they will need additional time. Attractive in theory, these programs, in practice, replace regular classroom time in the same subject. They add little additional time for learning.