I agree, elite schools (like MIT) have traditionally grounded their curricula upon a basis set of essential principles like "great books". At MIT, those were calculus through diff eq, physics, and engineering basics like statics and dynamics.
However, since around 1990, I suspect high school AP courses routinely overlap with said principle courses. So dropping MIT's four course intro to EECS probably became unavoidable after so many freshmen with AP course credits expressed frustration that taking those four EECS courses ("the MIT way") duplicated courses they'd already taken for credit in high school.
That is probably true. I think this is always a problem for elite schools, because you will always get the really motivated students who started a subject early and had a genuine interest in it, and these kids will never need what you are teaching in the introductory courses. The SICP approach was deep enough that anyone could find something to learn in it, if the teachers were willing to let the students run ahead at their own pace.
They also could have taken it as an inspiration to really make those courses advanced introductions to basic topics again (starting from counting, for example), and show that the AP course still had to leave out one or two interesting things, and how wide each of those fields really is.
However, since around 1990, I suspect high school AP courses routinely overlap with said principle courses. So dropping MIT's four course intro to EECS probably became unavoidable after so many freshmen with AP course credits expressed frustration that taking those four EECS courses ("the MIT way") duplicated courses they'd already taken for credit in high school.