I think a factor in Python vs Matlab is that Python grew into areas where Matlab was not entrenched. Also, students with an aptitude for programming and an eye for the market want to learn languages that are used by software developers. Very few engineers actually want to program in Matlab. If they can program, then they want to market themselves as programmers.

A benefit of Matlab remains that it all comes from one place, with one installer, meaning that you can get a classroom full of students up and running almost instantly. And it offers some relief for students who will never grasp programming, through its collection of pre-written apps.