Some of those institutions also signal (e.g., Williams, Harvey-Mudd, etc.) but most of them are relatively unknown and really do just compete on educational quality.
The caliber of student going into MIT is a lot different than UOP but the net ADD from MIT is probably not as big as you expect especially compared to any other accredited institution which UOP was not.
the net add of being surrounded by high caliber students is immeasurable in a positive way. The professors are experts, if the students can handle it, the professors deliver more material, faster. It's a huge add, there is no substitute for it.
Everyone I know who was going through their program had a structured pay scale where a graduate degree got them more money regardless of the degree. It was effective for signalling you wanted to get more money without learning much.
Class size is also a proxy metric for quality of teaching. If all your classes are auditorium lectures vs 20 student groups, it makes a difference. Of course, small classes with terrible instructors and awful lesson plans aren't better than competent lectures.
Of course, community colleges fill a lot of roles, and aren't just for transfer students, and they need to compete on those other things too.
seems like it would be useful to have available a "nutrition" label for colleges, which has to be based on facts.
Also there isn’t really much difference between Cornell, brown, or pen graduates from Any of the decent state schools. Except they are full of themselves more.
Honestly the graduates from 2nd tier state schools seem to have gotten the best education but they had adverse selection coming in because their more competitive peers went to higher ranked/named schools.