[lammalamma25]

This isn't a full explanation, but might be worth thinking about. CS bachelor's education track is unique enough it is hard to switch into. If you are electrical/mechanical/aerospace engineering you're taking a lot of the same classes until your 3 year or so. You can change your mind and switch majors within the hard engineering fields. It is similar if you want to switch from biology to chemistry etc. At least in my experience a CS degree starts and ends there. If you want to switch into CS you almost have to start your courses over unless you were computer engineering. So out of the average % of students switching majors, some switch out of CS, but very few switch into it.

[ghaff]

Electrical is fairly different from mechanical. Mechanical engineers do take some electrical engineering (and there are analogs between the two fields in areas like system dynamics although the examples are different) but there's quite a bit of fairly early-on coursework about fluids, material behavior, mechanical design, etc. Mechanical is closely related to aero and ocean but not so much electrical. (At least beyond basic core physics, calculus, etc.)