I have been on the hiring side, too. And the difference between a good enough college and an elite college is the
density of really good students.
If you have a fraction:
really good students
--------------------
all students in CS
Then this number tends to be much higher in elite colleges than good enough colleges.
This is my personal experience.
(Past) company did hire from non-elite colleges in case-by-case basis, but one time we wanted 4-5 freshers, we did go to the elite college.
All students of elite colleges aren't better than all students of good enough colleges, but the fraction is what is different.
In a a typical CS dept of 50 students, you can find 40-45 really good ones in elite colleges versus 3-8 in good-enough colleges.