I freely admit to being a poor college student. I did exactly what a large portion of students do, which is get ready to leave high school and go to college simply because it's the 'next step'. Halfway through my freshman year, I stopped going to class. I got kicked out (obviously), went to community college (where I also didn't go to class), and then took a year off. One of the things that I always took away from that is the simple fact that, not just academically, a lot of students just aren't socially or personally ready to go to college.
In a lot of ways, it's a broken system. As many of you pointed out, one of the driving forces of going to college now is to 'just get the piece of paper'. It now seems to be questioned a lot more when people don't immediatly go to college after high school, where it used to be something that wasn't expected. Echoing something that dmaul brought up, I was a social science major, and it really didn't net me a ton of skills that landed me a job. Really, the help was truly that I could apply for jobs that required a degree. Most of the skills that were valued in what I did (research, writing, presentations) were things that I've always had an innate ability to do, so aside from honing my skills, it didn't offer me a lot.
When I did decide to go back, I was a much better student, and most of what I truly enjoyed about college was the interaction with professors and actually discussing things pertaining to my major. It wasn't relevant job-related stuff, but it's something I liked delving into, both inside and outside of class. Which, really, goes back to the point... it's all about what you put into it.
Now that I deal with high school students every day, it's painfully clear that a large majority of them are either not ready for college (in many ways), or aren't headed into it with the right intentions. However, as brought up earlier, the system is about getting students to school, so no one takes any of that into account anymore. As the college choice became more of a 'right' than a privilege, it diluted it to a point where the students that *want* to be there is becoming a smaller and smaller percentage.
I could also go into the rant that it's symptomatic of how students are brought to be, but that's entirely too much to go into right now. Quickly, though: My friend relayed a story to me yesterday after his first day of permanent subbing for 8th grade students. He walked in, and one of the students immediatly stood up and asked 'Who the

are you?'. Do I think the chances of that student growing up to be a good college student are good? No. Do I think he'll definitely attend college directly after high school? With every certainty.
At the end of the day, a big part of the problem is just how many schools there are, and which one you attend. The more competetive schools likely have less issues, but what about the number of institutions that exist for no other reason than to cater to 2.5-3.0 GPA students with SAT scores of less than 1000? It's not a real pretty trend, and I haven't seen it going in a positive direction.
Right, not sure if any of that made a lot of sense, but hey.