Is college more about signaling, or is it more about giving people valuable skills?
Lumping all college degrees together confuses the issue. A computer science degree from a top-25 university gives you valuable skills. A philosophy degree from a non-top-25 university gives you no valuable skills.
Colleges like to describe all degrees as if they are similar, because most degrees give you no valuable skills, but the existence of really valuable degrees gives all degrees some signaling value.