I think the goals of having everyone graduate from high school and having all graduates be ready for college is unrealistic, since study at the college level requires above-average IQ, which most people do not have (by definition).
Study at the college level doesn't require above-average IQ (let alone above-average intelligence), though college graduates IIRC have a mean IQ that's higher than that of the general population. A well-prepared person with an average IQ could certainly go on to college and do well in a range of different fields-- you don't have to have the makings of a rocket scientist to successfully major in marketing, and degree programs are not all created equal. I believe that the biggest problem is poor teaching at the high school level and below.
It's certainly true that there are only so many highly skilled jobs available, of course, and from that perspective it doesn't make sense to send everyone to college, and the most able students should be the ones to have the educational opportunities required for those jobs, if one has to choose.
ETA: I skimmed the first part of this and found it interesting:
http://www.gnxp.com/blog/2008/09/college-is-still-best-pay-off.php
