Although there has been some research supportive of de-tracking, there has also been research finding it has negative effects, for example the paper discussed in the thread Tracking in the Era of College Prep for All.

The value of tracking depends on
(1) what subjects are tracked, and at what grade level
(2) whether good, distinct curricula are used for all tracks
(3) how well students are chosen for tracks both initially and later on
(4) the range of student ability
(5) the evaluation criteria used

and other factors. The question is probably not "Is tracking good?" but "Under what conditions is tracking good?".