I think that this is so much a matter of numbers. First, as was noted above, the overall enrollment at universities is much greater than it is at LACs. Penn State, for example, enrolled about 23,000 freshmen last year. Most of the LACs in PA enroll 500-600, so you’d need the enrollment of 40 LACs to “balance” PSU alone! So it makes sense that many more students matriculate at non-LACs. A lot of the big universities are what make their towns – Indiana University, Penn State – there’s not a lot there without the school. While some students avoid LACs because they want an urban environment, the big schools that are somewhat remote have awfully big student populations as well so I don’t think it’s just that.
It also makes sense, based on the numbers above, that when high school students are thinking about schools, they are far more likely to know people who went to non-LACs. This impacts not only which schools are recommended by family, friends, teachers, neighbors, etc., but what the expectations are for a college experience. If college means tailgating and attending football games, fight songs, etc., few LACs are going to be as gratifying as Ohio State or Clemson. And awareness is spread by sports as well. Even I know that Wisconsin has Badgers (watched the Rose Bowl) or that Duke has Blue Devils (March Madness)! When there are so many schools out there that people have heard of to choose from, why look for more? (I realize the CC crowd may not be typical in this regard!) The LACs fight an uphill battle on this front. (Consider the difference in attendance at the NCAA lax finals on the D1 day vs the D2+D3 days…)
There are also a lot of kids who went through public districts where there were several small elementary schools that fed into a couple of middle schools and ultimately a bigger high school. Going to school smaller than your high school (a LAC) can feel like the wrong progression.
Also, for a lot f students, the relationships they had with their high school teachers may make the proposition of “getting to know your profs” a negative. I think that this is one of the reason that so many kids from private schools are more likely to gravitate toward LACs – their experiences with faculty and their classroom experiences may have made them more interested in a participative model.
Also, as noted, there are a lot of students who want to pursue programs that are few LACs offer – nursing, engineering, physical therapy, accounting, sports management…. I also think that at a bigger school, a student can “find his tribe”. At LACs, the fit is much more important because there does tend to be a dominant vibe (if not tribe.) This can make the match-making much more challenging – vibe plus academic interest have to be right.
Personally, I’m a big fan of what LACs offer (and was thrilled when my kid narrowed his options to LACs), but I can easily understand – even for a kid who fully understands what that offering is – why a bigger university might be appealing and why disproportionately, so many more kids are headed off to non-LACs.