If the survey respondents are a cross-section of Americans, then they may well think of their nearby directional state U when asked generally about “college.” At most such universities, which educate the majority of 4-year students in the US, high school grades and (minimal) test scores are the whole enchilada, and most high school grads who want to enroll are admitted. If that’s your model, there isn’t any reason to think that the other factors are necessary.