We can try to make generalizations, but it would be quite hard since you are dealing with such a small pool of students in each MT class. At NYU Steinhardt, the biggest shift was that several of the classical students ended up changing to MT concentrations. So that added to the pool. But then a student dropped out totally (personal issues that affected grades) and one or two switched to academic majors.
One thing that I did notice is that several of the students ended up graduating with double majors. In D’s graduating class there were students who earned their BM in music (VP majors with MT concentration) along with degrees in math, dramatic literature, foreign language and journalism. Not all programs have that flexibility. Also several of those students brought in AP credits that freed up their schedules. D picked NYU for that reason. She graduated with her BM degree and a minor in business of entertainment, media and technology and another minor in English lit. She went into the program knowing she wanted to take classes outside of MT, since from the start she knew that she might want to do something in music and theatre in addition to performing.
So it is possible that some programs that offer flexibility to their MT students, may end up retaining more students since they can double major or minor and still graduate with a MT degree.